Zoom lens, and imaging device equipped with a zoom lens

Abstract

a first optical element group having a lens group and an optical element that bends the optical axis, arranged in this order from the object side to the image side; a second optical element group having negative refractive power; and a third optical element group having positive refractive power, wherein the lens group has positive refractive power and is located closer to the object side than the optical element, and the second optical element group and the third optical element group are configured to be movable along the optical axis so that the zoom lens changes magnification from a wide-angle end to a telephoto end.

Description

Technical Field

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

Background Art

[0002] Conventionally, various zoom lenses including an optical element that bends an optical axis are known.

[0003] For example, the zoom lens described in Japanese Patent Application Laid-Open No. 2007-34064 includes a first lens group including a first lens having a negative refractive power and a prism that bends an optical axis, arranged in order from an object side to an image side, a second lens group including two lenses, and a third lens group including three lenses. In the first lens group of this zoom lens, the first lens having a negative refractive power is arranged on the object side of the prism.

[0004] In this zoom lens, the dimension in the incident direction of light rays from an object can be reduced (that is, it is thin), but the F value at the wide-angle end is about F28, and it cannot be said that the aperture size is sufficient.

[0005] Also, in the zoom lens described in WO2021 / 085154A1, a prism is arranged on the object side of the lens group, that is, the prism is arranged on the most object side. In this zoom lens, the dimension in the incident direction of light rays can be reduced, but it is difficult to secure a sufficient size in the maximum diameter of the first lens group obtained by the focal length (EFL) / F value, and it is difficult to achieve a large aperture.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a zoom lens that can be placed in a thin imaging device, has a large aperture, and is capable of telephoto shooting, and an imaging device equipped with the zoom lens. [Means for solving the problem]

[0008] The zoom lens according to the present invention is They are arranged in order from the object side to the image side. A first optical element group having a lens group including at least one lens and an optical element that bends the optical axis, A second group of optical elements, which includes at least one lens and has negative refractive power, A third optical element group comprising at least one lens having positive refractive power, The aforementioned lens group has a positive refractive power and is positioned on the object side of the optical element. The second optical element group and the third optical element group are configured to be movable along the optical axis so that the zoom lens can change magnification between the wide-angle end and the telephoto end.

[0009] In the aforementioned zoom lens, Let the focal length of the first lens group be f1, and the focal length of the entire optical system at infinity focus at the telephoto end be ft. 0.5 ≤ f1 / ft ≤ 6 It may satisfy the requirement.

[0010] Furthermore, with the aforementioned zoom lens, When D12 is the distance along the optical axis from the object-side surface of the first optical element group to the object-side surface of the second optical element group, and TTL is the distance along the optical axis from the object-side surface of the first optical element group to the image plane, 0.2 ≤ D12 / TTL ≤ 0.7 It may satisfy the requirement.

[0011] Also, in the zoom lens, When the focal length of the third optical element group is f3, the focal length of the entire optical system at infinity focus at the wide-angle end is fw, and the focal length of the entire optical system at infinity focus at the telephoto end is ft, 0.2 ≦ f3 / √(fw × ft) ≦ 1.1 may be satisfied.

[0012] Also, in the zoom lens, When the focal length of the second optical element group is f2 and the focal length of the entire optical system at infinity focus at the telephoto end is ft, 0.2 ≦ |f2 / ft| ≦ 1.0 may be satisfied.

[0013] Also, in the zoom lens, The maximum effective diameter h23 of the light passing range in the second optical element group and the third optical element group may be 9 mm or less.

[0014] Also, in the zoom lens, The distance on the optical axis from the most object-side surface of the first optical element group to the image plane may be 40 mm or less.

[0015] Also, the zoom lens includes an aperture for adjusting the amount of light passing through, The aperture may be arranged between the image-side surface of the optical element in the first optical element group and the most object-side surface of the third optical element group.

[0016] Also, the zoom lens At least one surface of at least one lens in the third optical element group may be an aspherical surface.

[0017] Also, in the zoom lens, At least one lens in the third optical element group may be made of plastic.

[0018] In addition, the imaging device according to the present invention is any one of the above zoom lenses, and an imaging element that is disposed at the image plane position of the zoom lens and converts the formed optical image into an electrical signal.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of the imaging device according to the present embodiment. [Figure 2] FIG. 2 is a lens configuration diagram of the zoom lens included in the imaging device. [Figure 3] FIG. 3 is a lens configuration diagram of the zoom lens of Example 1, showing a lens configuration diagram of the wide-angle end and the telephoto end. ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​As shown in Figure 1, the imaging device 100 includes a zoom lens (optical system) 1, which is arranged so that at least a portion of it is built into the imaging device body 101, and an image sensor (image element) 5, which is positioned at the imaging position (image plane position) of the zoom lens 1. Specifically, the imaging device 100 includes the imaging device body 101, the zoom lens (optical system) 1, the image sensor 5, and a display unit 102 such as a liquid crystal screen that displays the imaging (image) data output from the image sensor 5. The imaging device 100 also includes a control unit (arithmetic unit) 103 that controls each component and processes signals from the image sensor 5, etc., and a power supply 104.

[0023] The image sensor 5, positioned at the image-forming plane of the zoom lens 1, is an element that converts the optical image formed by the zoom lens 1 into an electrical signal (imaging data). In this embodiment, the image sensor 5 is a CMOS image sensor. Since the image-forming plane of the zoom lens 1 and the light-receiving surface of the image sensor 5 are positioned at the same location, the image sensor (more specifically, the light-receiving surface of the image sensor) may be referred to as the image plane 5 below.

[0024] As shown in Figure 2, the zoom lens 1 comprises at least a first optical element group G1, a second optical element group G2, and a third optical element group G3, arranged sequentially along the optical axis C from the object side to the image side. Each of these optical element groups G1, G2, and G3 includes at least one optical element such as a lens. The zoom lens 1 of this embodiment has, in order along the optical axis C from the object side to the image side, the first optical element group G1, the second optical element group G2, the third optical element group G3, and an optical filter (an IR filter in this example) 6. The zoom lens 1 also has an aperture (aperture device) 7 positioned at a predetermined position on the optical axis C, and protective glass 8 positioned on the object side of the first optical element group G1. The aperture 7 of this embodiment is positioned on the object side of the third optical element group G3 and moves along the optical axis C together with the third optical element group G3 during zooming and focusing.

[0025] The second optical element group G2 and the third optical element group G3 are configured to be movable along the optical axis C, respectively, so that the zoom lens 1 can change magnification between the wide-angle end and the telephoto end (see Figure 3).

[0026] The first optical element group G1 includes a lens group 10 containing at least one lens, and a reflective optical element (optical element) 15 that bends the optical axis C. The lens group 10 has a positive refractive power and is positioned closer to the object than the reflective optical element 15. In the first optical element group G1 of this embodiment, the lens group 10 includes one lens (first lens) 11, and the reflective optical element 15 is a prism having a reflective surface 15a that bends the incident light ray (optical axis C) when reflected, and is made of glass. Note that in Figure 2, the reflective optical element (prism) 15 is represented by a rectangle. The same applies to Figures 3 and 6.

[0027] Furthermore, the second optical element group G2 includes at least one lens and has a negative refractive power. In this embodiment, the second optical element group G2 includes two lenses (second lens 21, third lens 22). Furthermore, the third optical element group G3 includes at least one lens and has a positive refractive power. In this embodiment, the third optical element group G3 includes five lenses (fourth lens 31 to eighth lens 35).

[0028] Furthermore, the zoom lens 1 has a lens barrel 16 that holds each optical element group G1 to G3. The lens barrel 16 of this embodiment includes a bent portion 16A into which light rays (light from an object) are incident and which bends the optical axis C of the incident light rays, and a main body portion 16B that is built into the imaging device body 101. The bent portion 16A is the part in which the first optical element group G1 is located, and the main body portion 16B is the part in which the second optical element group G2 and the third optical element group G3 are located.

[0029] In this embodiment of the zoom lens 1, the lens group 10, the second optical element group G2, and the third optical element group G3 are names for convenience and include those composed of only one optical element (lens, etc.). That is, each of the lens group 10, the second optical element group G2, and the third optical element group G3 includes at least one lens, etc. (optical element).

[0030] Here, if the focal length of the first optical element group is f1 and the focal length of the entire optical system at infinity focus at the telephoto end is ft, the zoom lens 1 may satisfy the following condition (1). 0.5 ≤ f1 / ft ≤ 6 ···(1) Note that the total focal length of the optical system when focused at infinity at the telephoto end is the total focal length of the optical system when zoomed to the telephoto end and focused at infinity. Similarly, the total focal length of the optical system when focused at infinity at the wide-angle end is the total focal length of the optical system when zoomed to the wide-angle end and focused at infinity.

[0031] If the value of f1 / ft is less than the lower limit (0.5), the positive refractive power of the first optical element group G1 is too strong, causing the distance between the first lens 11 and the second optical element group G to decrease. This makes it impossible to secure space for the reflective optical element 15 to bend the optical axis C. On the other hand, if the value of f1 / ft is greater than the upper limit (6), the positive refractive power of the first optical element group G1 is too weak, causing the dimension (total length) of the optical system (zoom lens) 1 along the optical axis C to increase at the telephoto end, making it difficult to make the zoom lens 1 compact. In other words, by satisfying the above condition (1) in the zoom lens 1, it is possible to balance securing space for the reflective optical element 15 with making the dimensions of the zoom lens 1 compact along the optical axis C.

[0032] Furthermore, from the viewpoint of securing space for the reflective optical element 15 and miniaturizing the dimensions of the zoom lens 1 along the optical axis C, it is more preferable that the zoom lens 1 satisfies the following condition (1a). 1 ≤ f1 / ft ≤ 5 ···(1a)

[0033] Furthermore, in this zoom lens 1, when D12 is defined as the distance along the optical axis C from the object-side surface 11a of the first optical element group G1 (the object-side surface of the first lens 11) to the object-side surface 21a of the second optical element group G2 (the object-side surface of the second lens 21), and TTL is defined as the distance along the optical axis C from the object-side surface 11a of the first optical element group G1 to the image plane 5, the zoom lens 1 may satisfy the following condition (2). 0.2 ≤ D12 / TTL ≤ 0.7 ···(2)

[0034] If the value of D12 / TTL is less than the lower limit (0.2), the distance between the first lens 11 and the second optical element group G2 in the optical axis C direction becomes too small, and there is insufficient space to arrange the reflective optical element 15. On the other hand, if the value of D12 / TTL is greater than the upper limit (0.7), the distance between the first lens 11 and the second optical element group G2 in the optical axis C direction becomes too large, and it is not possible to make the dimensions of the zoom lens 1 compact along the optical axis C. In other words, by satisfying the above condition (2) in the zoom lens 1, it is possible to balance securing space for the reflective optical element 15 with making the dimensions of the zoom lens 1 compact along the optical axis C.

[0035] Furthermore, from the viewpoint of securing space for the reflective optical element 15 and miniaturizing the dimensions of the zoom lens 1 along the optical axis C, it is more preferable that the zoom lens 1 satisfies the following condition (2a). 0.25≦D12 / TTL≦0.65 (2a)

[0036] Furthermore, in this zoom lens 1, when the focal length of the third optical element group G3 is f3, the focal length of the entire zoom lens (optical system) when in focus at the wide-angle end is fw, and the focal length of the entire zoom lens (optical system) when in focus at the telephoto end is ft, the zoom lens 1 may satisfy the following condition (3). 0.2 ≤ f³ / √(fw × ft) ≤ 1.1 ···(3)

[0037] The above conditional equation (3) defines the ratio of the focal length f3 of the third optical element group G3 to the effective focal length of the zoom lens 1. Furthermore, among the optical element groups G1 to G3 that constitute the zoom lens 1, the third optical element group G3 is the main group. Therefore, when the third optical element group G3 is within an appropriate refractive power range, that is, when the above conditional equation (3) is satisfied in the zoom lens 1, the magnification ratio of the second optical element group G2 and the third optical element group G3 becomes appropriate, and the performance from the wide-angle end to the telephoto end is optimized.

[0038] Specifically, when the value of f3 / √(fw×ft) falls below the lower limit (0.2), the refractive power of the third optical element group G3 increases, and the refractive power of the second optical element group G2 also increases. This leads to larger fluctuations in field curvature, spherical aberration, etc., resulting in larger performance variations from the wide-angle end to the telephoto end, making it difficult to ensure good performance across the entire range from wide-angle to telephoto. On the other hand, when the value of f3 / √(fw×ft) falls above the upper limit (1.1), the refractive power of the third optical element group G3 decreases, increasing the dimensions of the zoom lens 1 along the optical axis C, and weakening the correction of spherical aberration, making it difficult to construct a zoom lens (optical system) 1 with a bright F-number.

[0039] Furthermore, it is more preferable for zoom lens 1 to satisfy the following condition (3a). 0.25≦f3 / √(fw×ft)≦1.0 (3a)

[0040] Furthermore, in this zoom lens 1, when the focal length of the second optical element group G2 is f2 and the total focal length of the zoom lens (optical system) at infinity focus at the telephoto end is ft, the zoom lens 1 may satisfy the following condition (4). 0.2 ≤ |f² / ft| ≤ 1.0 ···(4)

[0041] Conditional equation (4) defines the ratio of the focal length f2 of the second optical element group G2 to the total focal length ft of the zoom lens (optical system) when in focus at infinity at the telephoto end. In the zoom lens 1 of this embodiment, when changing magnification from the wide-angle end to the telephoto end, the first optical element group G1 is fixed, and the second optical element group G2 and the third optical element group G3 move in the direction of the optical axis C as a magnification group, following different trajectories so that the distance between them decreases. Based on the relationship between the amount of movement of the zooming groups G2 and G3 during magnification and the refractive power (1 / focal length) of the zooming groups G2 and G3, if the zooming groups G2 and G3 exceed a certain refractive power range, compactness and high performance cannot be obtained in the zoom lens 1.

[0042] Specifically, if the value of |f2 / ft| exceeds the upper limit (1.0), the refractive power of the second optical element group G2 becomes too weak, and the amount of movement during magnification increases. As a result, the overall length (dimension along the optical axis C) of the zoom lens 1 increases in order to maintain the magnification, making it difficult to make the zoom lens 1 compact. On the other hand, if the value of |f2 / ft| falls below the lower limit (0.2), the refractive power of the second optical element group G2 becomes too strong, and fluctuations such as field curvature during magnification increase, disrupting the overall performance balance.

[0043] Furthermore, from the standpoint of miniaturization and high performance, it is more preferable for zoom lens 1 to satisfy the following condition (4a). 0.3≦|f2 / ft|≦0.9 (4a)

[0044] Furthermore, in this zoom lens 1, the maximum effective diameter h23 of the light ray passage range between the second optical element group G2 and the third optical element group G3 may be 9 mm or less.

[0045] This configuration makes it possible to achieve a compact size that can be used in portable imaging devices such as smartphones. In this embodiment, the maximum effective diameter h23 of the light ray passage range in the second optical element group G2 and the third optical element group G3 is the outer diameter of the fourth lens 31.

[0046] Furthermore, in this zoom lens 1, the distance on the optical axis C from the object-side surface 11a of the first optical element group G1 to the image plane 5 may be 40 mm or less.

[0047] This configuration also makes it possible to achieve a compact size that can be used in a portable imaging device 100 such as a smartphone.

[0048] Furthermore, in this zoom lens 1, at least one surface of at least one lens (fourth lens 31 to eighth lens 35) in the third optical element group G3 may be an aspherical surface.

[0049] Thus, by making at least one surface of at least one lens 31-35 of the third optical element group G3 aspherical, it is advantageous to improve the performance of the zoom lens 1. In particular, in lenses with positive refractive power, having at least one surface aspherical significantly improves the correction of spherical aberration.

[0050] Furthermore, in this zoom lens 1, at least one lens (fourth lens 31 to eighth lens 35) in the third optical element group G3 may be made of plastic.

[0051] This configuration makes it possible to reduce costs and the weight of the zoom lens 1.

[0052] The zoom lens 1 described above can be placed in a thin imaging device 100, and it is possible to take telephoto shots with a large aperture. Further details are as follows.

[0053] In the zoom lens 1 of this embodiment, the first optical element group G1 having positive refractive power, the second optical element group G2 having negative refractive power, and the third optical element group G3 having positive refractive power are arranged in that order from the object side. By weakening the contribution of the first optical element group G1 to the refractive power of the entire zoom lens 1 system and creating a weak telephoto configuration with positive refractive power, a large-aperture telephoto zoom lens 1 can be obtained.

[0054] Furthermore, in the zoom lens 1 of this embodiment, the second optical element group G2 having negative refractive power and the third optical element group G3 having positive refractive power move toward each other along the optical axis C as a zooming group, thereby keeping the image plane position constant.

[0055] In this embodiment, when the zoom lens 1 is changed from the wide-angle end to the telephoto end, the second optical element group G2 moves in one direction from the object side to the image side. However, the second optical element group G2 may be configured to move towards the object side from a certain point during the change in zoom from the wide-angle end to the telephoto end. Even with this configuration, the third optical element group G3 moves from the image side to the object side in conjunction with the movement of the second optical element group G2 during the zoom change.

[0056] Furthermore, in the zoom lens 1 of this embodiment, the first optical element group G1 is fixed with respect to the optical axis C. Therefore, the second optical element group G2 is used for focusing and image stabilization in the zoom lens 1. The third optical element group G3 is also used for focusing and image stabilization in the zoom lens 1.

[0057] Furthermore, in the zoom lens 1 of this embodiment, the first optical element group G1 having positive refractive power includes a first lens 11 having positive refractive power and a reflective optical element 15 having a reflective surface 15a such as a prism. Thus, in the zoom lens 1, the light ray (optical axis C) is bent in the first optical element group G1 (bent by 90° in the example of this embodiment). Therefore, by arranging the zoom lens 1 so that the overall length direction of the zoom lens (optical system) 1 (the dimension along the optical axis C of the part on the image plane side of the reflective optical element 15) coincides with the length direction of the imaging device (smartphone) 100 (up and down direction in Figure 1), the dimensions of the imaging device (smartphone) 100 in the effective diameter direction of the zoom lens 1 (left and right direction in Figure 1), i.e., the thickness of the imaging device 100, can be reduced.

[0058] Furthermore, by using a lens with positive refractive power as the first lens 11, the light rays that have passed through the first lens 11 converge as they travel through the second optical element group G2, which allows the effective diameter of each optical element group G2 and G3 on the image side of the reflective optical element 15 to be reduced, that is, the thickness of the imaging device (smartphone) 100 can be reduced more effectively.

[0059] It should be noted that the zoom lens 1 and the imaging device 100 equipped with the zoom lens 1 of the present invention are not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0060] In the zoom lens 1 of the above embodiment, the aperture 7 is located on the object side of the third optical element group G3, but the configuration is not limited to this. The aperture 7 only needs to be located between the image-side surface 15b of the reflective optical element 15 of the first optical element group G1 and the object-side surface 31a of the third optical element group G3. With this configuration, the width of the light rays incident on the third optical element group G3 is limited, thereby ensuring the amount of light during magnification and suppressing fluctuations in the performance of the zoom lens 1.

[0061] Furthermore, although the reflective optical element 15 of the zoom lens 1 in the above embodiment is composed of a prism and the optical axis (optical path) C is bent by the reflective surface 15a within the prism, the configuration is not limited to this. The reflective optical element 15 may be a reflective mirror or the like.

[0062] Next, embodiments 1 and 2 of the imaging apparatus of the present invention will be described. In each of the following embodiments, the same reference numerals will be used for the components of the zoom lens 1 in the above embodiment and the components corresponding to them. In the tables in each of the following embodiments, r is the radius of curvature, d is the lens thickness or lens spacing, Nd is the refractive index of the d line, and Vd is the Abbe number based on the d line. Furthermore, the aspherical surface profile is given, for example, by the following equation 1.

number

[0063] Furthermore, each longitudinal aberration diagram shows, from left to right, spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)). In the spherical aberration diagram, the vertical axis represents the F-number (indicated as FNO in the diagram), with the solid line representing the d-line, the dashed line representing the F-line, and the dashed line representing the C-line. In the astigmatism diagram, the vertical axis represents the field of view, with the solid line representing the sagittal plane and the dashed line representing the meridional plane. In the distortion diagram, the vertical axis represents the field of view.

[0064] Furthermore, Table 1 shows the various data for each of the following Examples 1 and 2. [Table 1]

[0065] [Example 1] Figure 3 is a lens configuration diagram showing the positions of the lenses 11, 15, 21, 22, and 31-35 that constitute the zoom lens 1 at the wide-angle and telephoto ends of this embodiment 1. Specifically, the zoom lens 1 of this embodiment 1 comprises, in order from the object side to the image side, a first optical element group G1 having positive refractive power, a second optical element group G2 having negative refractive power, and a third optical element group G3 having positive refractive power. In this zoom lens 1, the incident light ray passes through the first optical element group G1, where its optical axis C is bent by 90 degrees, and then passes through the second and third optical element groups G2 and G3 to form an image on the imaging surface of an image sensor 5 such as a CMOS. In addition, a UVIR cut filter 6 that adjusts the wavelength of the incident light is placed between the third optical element group G3 and the image sensor (imaging surface) 5.

[0066] In this zoom lens 1, the first optical element group G1 includes, in order from the object side, a first lens 11 (lens group 10) having positive refractive power and a prism (reflective optical element) 15 that bends the optical path. The second optical element group G2 includes, in order from the object side, a second lens 21 having positive refractive power and a third lens 22 having negative refractive power. In the third lens 22 of the second optical element group G2, the object side and the image side are concave. The third optical element group G3 includes, in order from the object side, an aperture 7, a fourth lens 31 having positive refractive power, a fifth lens 32 having positive refractive power, a sixth lens 33 having negative refractive power, a seventh lens 34 having positive refractive power, and an eighth lens 35 having negative refractive power. In the fourth lens 31 of the third optical element group G3, the object side is convex.

[0067] Furthermore, in this zoom lens 1, the zoom function is achieved by the movement of the second optical element group G2 and the third optical element group G3 in the direction of the optical axis C. In addition, in the zoom lens 1, focusing is performed from infinity to close by the movement of the second optical element group G2 along the optical axis C at each zoom position. Furthermore, vibration correction is performed in the zoom lens 1 by the shifting of the third optical element group G3 in a plane direction perpendicular to the optical axis C in response to vibrations applied to the zoom lens 1. Alternatively, vibration correction may be performed in the zoom lens 1 by the shifting of the image sensor (shooting surface) 5 in a plane direction perpendicular to the optical axis C in response to the vibrations.

[0068] Figure 4 shows the longitudinal aberration diagram when the lens is focused at infinity at the wide-angle end, and Figure 5 shows the longitudinal aberration diagram when the lens is focused at infinity at the telephoto end. Furthermore, Table 2 below shows the surface data for each lens, Table 3 shows the aspherical data for each lens, Table 4 shows various data when the lens is focused at infinity, Table 5 shows the position data of the focus group when the lens is focused at an object distance of 500 mm, and Table 6 shows the group data for the zoom lens.

[0069] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6]

[0070] [Example 2] Figure 6 is a lens configuration diagram showing the positions of the lenses 11, 15, 21, 22, and 31-37 that constitute the zoom lens 1A at the wide-angle and telephoto ends of this embodiment 1. Specifically, the zoom lens 1A of this embodiment 2 comprises, in order from the object side to the image side, a first optical element group G1 having positive refractive power, a second optical element group G2 having negative refractive power, and a third optical element group G3 having positive refractive power. In this zoom lens 1A, the incident light ray passes through the first optical element group G1, where its optical axis C is bent by 90 degrees, and then passes through the second and third optical element groups G2 and G3 to form an image on the imaging surface of an image sensor 5 such as a CMOS. In addition, a UVIR cut filter 6 that adjusts the wavelength of the incident light is placed between the third optical element group G3 and the image sensor (imaging surface) 5.

[0071] In this zoom lens 1A, the first optical element group G1 includes, in order from the object side, a first lens 11 (lens group 10) having positive refractive power, and a prism (reflective optical element) 15 that bends the optical path. The second optical element group G2 includes, in order from the object side, a second lens 21 having positive refractive power, a third lens 22 having negative refractive power, and an aperture 7. In the third lens 22 of the second optical element group G2, the object side and the image side are concave. The third optical element group G3 includes, in order from the object side, a fourth lens 31 having positive refractive power, a fifth lens 32 having positive refractive power, a sixth lens 33 having negative refractive power, a seventh lens 34 having negative refractive power, an eighth lens 35 having positive refractive power, a ninth lens 36 having negative refractive power, and a tenth lens 38 having positive refractive power. In the fourth lens 31 of this third optical element group G3, the side surface of the object is convex.

[0072] Furthermore, in this zoom lens 1A, the zoom function is achieved by the movement of the second optical element group G2 and the third optical element group G3 in the direction of the optical axis C. In addition, in the zoom lens 1A, focusing is performed from infinity to close by the movement of the second optical element group G2 along the optical axis C at each zoom position. Furthermore, vibration correction is performed in the zoom lens 1A by the shifting of the third optical element group G3 in a plane direction perpendicular to the optical axis C in response to vibrations applied to the zoom lens 1. Alternatively, vibration correction may be performed in the zoom lens 1 by the shifting of the image sensor (shooting surface) 5 in a plane direction perpendicular to the optical axis C in response to the vibrations.

[0073] Figure 7 shows the longitudinal aberration diagram when the lens is focused at infinity at the wide-angle end, and Figure 8 shows the longitudinal aberration diagram when the lens is focused at infinity at the telephoto end. Furthermore, Table 7 shows the surface data for each lens, Table 8 shows the aspherical data for each lens, Table 9 shows various data when the lens is focused at infinity, Table 10 shows the position data of the focus group when the lens is focused at an object distance of 500 mm, and Table 11 shows the group data for the zoom lens.

[0074] [Table 7] [Table 8] [Table 9] [Table 10] [Table 11]

[0075] In order to express the present invention, the embodiments have been adequately and sufficiently described above with reference to the drawings. However, those skilled in the art should recognize that it is easy to modify and / or improve upon the above embodiments. Therefore, unless such modifications or improvements implemented by those skilled in the art deviate from the scope of the claims, such modifications or improvements shall be considered to be included within the scope of the claims. [Explanation of Symbols]

[0076] 1, 1A: Zoom lens 5: Image sensor 8: Protective glass 10: Lens group 11: First Lens 11a: The object-side surface of the first lens (the surface of the first optical element group closest to the object) 15: Reflective optical element (prism) 15a: Reflective surface 15b: Image-side surface of the reflective optical element 16: Telescope tube 16A: Bent part 16B: Main body 21: Second lens 21a: The object-side surface of the second lens (the surface closest to the object in the second optical element group) 22: Third Lens 31-38: Fourth to Eleventh Lenses 31a: The side of the third optical element group that is closest to the object. 100: Imaging device 101: Imaging device main unit 102: Display section 103: Control Unit (Calculation Unit) 104: Power supply C: Optical axis G1: First optical element group G2: Second optical element group G3: Third optical element group

Claims

1. They are arranged in order from the object side to the image side. A first optical element group consisting of a lens group including at least one lens and an optical element that bends the optical axis, A second group of optical elements, which includes at least one lens and has negative refractive power, It consists of a third optical element group that includes at least one lens and has positive refractive power, The aforementioned lens group has a positive refractive power and is positioned on the object side of the optical element. The second optical element group and the third optical element group are configured to be movable along the optical axis so that the zoom lens can change magnification between the wide-angle end and the telephoto end. When the focal length of the first optical element group is f1, and the focal length of the entire optical system at infinity focus at the telephoto end is ft, 0.5 ≤ f1 / ft ≤ 6 A zoom lens that meets the requirements.

2. Arranged in order from the object side to the image side, A first optical element group consisting of a lens group including at least one lens and an optical element that bends the optical axis, A second group of optical elements, which includes at least one lens and has negative refractive power, It consists of a third optical element group that includes at least one lens and has positive refractive power, The aforementioned lens group has a positive refractive power and is positioned on the object side of the optical element. The second optical element group and the third optical element group are configured to be movable along the optical axis so that the zoom lens can change magnification between the wide-angle end and the telephoto end. When the focal length of the third optical element group is f3, the focal length of the entire optical system when in focus at the wide-angle end is fw, and the focal length of the entire optical system when in focus at the telephoto end is ft, 0.2 ≤ f³ / √(fw × ft) ≤ 1.1 A zoom lens that meets the requirements.

3. Arranged in order from the object side to the image side, A first optical element group consisting of a lens group including at least one lens and an optical element that bends the optical axis, A second group of optical elements, which includes at least one lens and has negative refractive power, It consists of a third optical element group that includes at least one lens and has positive refractive power, The aforementioned lens group has a positive refractive power and is positioned on the object side of the optical element. The second optical element group and the third optical element group are configured to be movable along the optical axis so that the zoom lens can change magnification between the wide-angle end and the telephoto end. When the focal length of the second optical element group is f2, and the focal length of the entire optical system at infinity focus at the telephoto end is ft, 0.2≦|f2 / ft|≦1.0 A zoom lens that meets the requirements.

4. When D12 is the distance along the optical axis from the object-side surface of the first optical element group to the object-side surface of the second optical element group, and TTL is the distance along the optical axis from the object-side surface of the first optical element group to the image plane, 0.2 ≤ D12 / TTL ≤ 0.7 A zoom lens according to any one of claims 1 to 3, which satisfies the following conditions.

5. The zoom lens according to any one of claims 1 to 3, wherein the maximum effective diameter h23 of the light ray passage range in the second optical element group and the third optical element group is 9 mm or less.

6. The zoom lens according to any one of claims 1 to 3, wherein the distance on the optical axis from the object-side surface of the first optical element group to the image plane is 40 mm or less.

7. Equipped with an aperture that adjusts the amount of light passing through, The zoom lens according to any one of claims 1 to 3, wherein the aperture is positioned between the image-side surface of the optical element in the first optical element group and the object-side surface of the third optical element group.

8. The zoom lens according to any one of claims 1 to 3, wherein at least one surface of at least one lens in the third optical element group is aspherical.

9. The zoom lens according to any one of claims 1 to 3, wherein at least one lens in the third optical element group is made of plastic.

10. A zoom lens according to any one of claims 1 to 3, An imaging device comprising an image sensor positioned at the image plane of the zoom lens and converting the formed optical image into an electrical signal.

Images