Lens device and image capturing device

Abstract

To provide a compact lens device.SOLUTION: A lens device (100) disclosed herein comprises multiple lens groups consisting of a first lens group (L1), second lens group (L2), and rear lens group (L3), a first holding unit (11) for holding the first lens group, a second holding unit (12) configured to hold the second lens group and move along an optical axis together with the second lens group, and a drive unit (20) for driving the second holding unit along the optical axis, arranged in order from the object side to the image side, and is configured such that a distance between each pair of adjacent lens groups of the plurality of lens groups changes while zooming from the wide-angle end to the telephoto end. A first end (201) of the drive unit on the most object side in the optical axis direction is located at a position matching a position (P1) of a second end (121) of the second holding unit on the most object side or at a position (P2) on the image side of the second end.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lens apparatus and an imaging apparatus. [Background technology]

[0002] Patent Document 1 discloses a lens device having an optical system consisting of five lens groups, in order from the object side to the image side, namely, a first lens group, a second lens group, a third lens group, a fourth lens group, and a fifth lens group. Patent Document 1 also discloses that a third lens group is driven by a third group motor to perform electric zoom (power zoom), and a focusing motor (voice coil motor) is used to drive the second lens group to perform focusing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-83775 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the configuration of Patent Document 1 is adopted in a lens device that performs electric zoom by driving the second lens group, the movement stroke of the second lens group may cause the motor that drives the second lens group to interfere with the first lens group or the holding frame that holds the first lens group. On the other hand, if an attempt is made to position the motor in a way that avoids such interference, the radial size of the lens device will increase.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a compact lens device. [Means for solving the problem]

[0006] A lens device according to one aspect of the present invention comprises a plurality of lens groups consisting of a first lens group, a second lens group, and a rear lens group, arranged in order from the object side to the image side, a first holding portion that holds the first lens group, a second holding portion that holds the second lens group and moves together with the second lens group in the optical axis direction, and a driving portion that drives the second holding portion in the optical axis direction, the driving portion having a first driving member including a first coil and a second driving member including a second coil, and in the optical axis direction, a first end portion of the driving portion closest to the object is arranged at the same position as a second end portion of the second holding portion closest to the object, or at a position closer to the image side than the second end portion, and in the optical axis direction, the position of the end portion of the first coil closest to the object side and the position of the end portion of the second coil closest to the object side are different in the optical axis direction.

[0007] Other objects and features of the present invention will be described in the following embodiments. Effect of the Invention

[0008] According to the present invention, a compact lens device can be provided. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a lens device according to a first embodiment. [Diagram 2] FIG. 11 is a cross-sectional view of a lens device according to a second embodiment. [Diagram 3] FIG. 11 is a cross-sectional view of a lens device according to a third embodiment. [Figure 4] FIG. 2 is a schematic diagram of an imaging device in each embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] (First embodiment) First, a lens device 100 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of the lens device 100. In Fig. 1, the left side is the object side, and the right side is the image side. Note that Fig. 1 shows only configurations that are directly related to the description of this embodiment, and configurations that are not directly related to the description of this embodiment are omitted.

[0012] The lens device 100 has a plurality of lens groups (imaging optical system) including a first lens group L1, a second lens group L2, and a rear lens group arranged in order from the object side to the image side. An optical image formed by the plurality of lens groups is focused on an image surface IP. Note that in FIG. 1, only the third lens group L3 arranged adjacent to the second lens group L2 on the image side of the second lens group L2 is shown as the rear lens group, but this embodiment is not limited to this. As long as the rear lens group includes at least the third lens group L3, it may further include at least one lens group on the image side of the third lens group L3. Note that the lens group is not limited to being composed of a plurality of lenses, and may be composed of one lens.

[0013] In the lens group, the interval between adjacent lens groups changes during zooming from the wide-angle end to the telephoto end. In this embodiment, during zooming, the second lens group L2 moves in a direction along the optical axis OA (optical axis direction) with a movement stroke MS indicated by an arrow in FIG. 1. In addition, in this embodiment, the first lens group L1 does not move during zooming. That is, the total lens length (the length on the optical axis from the lens surface closest to the object to the lens surface closest to the image of the lens groups constituting the imaging optical system plus the back focus) does not change (total length is fixed). In this embodiment, the lens device 100 has a diaphragm (aperture diaphragm) SP that moves together with the second lens group L2, but is not limited thereto.

[0014] The first holding frame (first holding section) 11 holds the first lens group L1. The second holding frame (second holding section) 12 holds the second lens group L2 and moves together with the second lens group L2 in the optical axis direction. In the radial direction, the second holding frame 12 is smaller than the first holding frame 11. The voice coil motor (driving section) 20 is connected to the second holding frame 12 and configured to be able to transmit a driving force to the second holding frame 12, thereby driving the second holding frame 12 in the optical axis direction. The lens device 100 is capable of electric zoom, and the voice coil motor 20 drives the second holding frame 12 by control based on a user's operation or a user's instruction.

[0015] The voice coil motor 20 has a coil 21, a magnet 22, and a yoke 23. The coil 21 is provided integrally with the second holding frame 12. The magnet 22 and the yoke 23 are provided in the lens barrel 31, and form a magnetic field to move the coil 21.

[0016] In the lens device 100, to drive the second lens group L2 with the voice coil motor 20, it is necessary to arrange the coil 21, the magnet 22, and the yoke 23 in the vicinity of the second lens group L2. Because the magnet 22 and the yoke 23 are large, there is a possibility that they may interfere (contact or collide) with, for example, the first lens group L1 or the first holding frame 11 during zooming. If the voice coil motor 20 is retracted in a direction (radial direction) away from the optical axis OA to avoid interference, the lens device 100 becomes larger.

[0017] Therefore, in this embodiment, the positional relationship between the second holding frame 12 and the voice coil motor 20 in the optical axis direction is set so as to avoid interference between the first holding frame 11 and the voice coil motor 20. That is, in this embodiment, the front end 201 of the voice coil motor 20 (the first end of the voice coil motor 20 closest to the object) is disposed at a position P2 on the image side of the position P1 of the front end 121 of the second holding frame 12 (the second end of the second holding frame 12 closest to the object). However, this embodiment is not limited to this, and the front end 201 of the voice coil motor 20 may be at the same position (P1=P2) as the position P1 of the front end 121 of the second holding frame 12 in the optical axis direction. In other words, the front end 201 of the voice coil motor 20 does not protrude further toward the object side than the front end 121 of the second holding frame 12.

[0018] With this configuration, even when the second lens group L2 moves in the optical axis direction during zooming, it is possible to achieve a reduction in size of the lens device 100 while avoiding interference between the voice coil motor 20 and the first lens group L1 or the first retaining frame 11. According to this embodiment, the voice coil motor 20 is disposed on the outside of the second retaining frame 12, which contributes to a reduction in size of the lens device 100 in the radial direction, i.e., in the direction perpendicular to the optical axis OA (direction perpendicular to the optical axis).

[0019] In this embodiment, the length from the outermost end to the innermost end in the radial direction (direction perpendicular to the optical axis direction) of yoke 23 is shorter than the length in the optical axis direction from the end closest to the object side to the end closest to the image side of yoke 23. With this configuration, the radial size of lens device 100 can be reduced.

[0020] Second embodiment Next, a lens device 100a according to a second embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view of the lens device 100a. In Fig. 2, the left side is the object side, and the right side is the image side. Note that Fig. 2, like Fig. 1, only configurations directly related to the description of this embodiment are extracted and shown, and configurations not directly related to the description of this embodiment are omitted.

[0021] The lens device 100a of this embodiment differs from the lens device 100 of the first embodiment in that it has a voice coil motor 20a instead of the voice coil motor 20. Other configurations and operations of the lens device 100a are common to the lens device 100, and therefore description thereof will be omitted.

[0022] The voice coil motor 20a has a coil 21a, a magnet 22a, and a yoke 23a, and is disposed behind (on the image side) the second holding frame 12 that holds the second lens group L2. That is, when viewed in the optical axis direction from the object side to the image side (when viewed from the front of the lens device 100a), at least a portion of each of the coil 21a, the magnet 22a, and the yoke 23a of the voice coil motor 20a overlaps with at least a portion of the second holding frame 12. In this embodiment, the front end 201a of the voice coil motor 20a (the first end of the voice coil motor 20a closest to the object) is disposed at a position closer to the image side than the position of the front end 121 of the second holding frame 12 (the second end of the second holding frame 12 closest to the object).

[0023] With this configuration, even when the second lens group L2 moves in the optical axis direction during zooming, it is possible to achieve a compact lens device 100a while avoiding interference between the voice coil motor 20a and the first lens group L1 or the first retaining frame 11. According to this embodiment, the voice coil motor 20a is disposed on the image side of the second retaining frame 12, which contributes to a compact size in the optical axis direction of the lens device 100a.

[0024] In this embodiment, when viewed in the optical axis direction from the object side to the image side, at least a part of the voice coil motor 20a and at least a part of the first holding frame 11 overlap with each other. This makes it possible to reduce the radial size of the lens device 100a.

[0025] Third embodiment Next, a lens device 100b according to a third embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view of the lens device 100b. In Fig. 3, the left side is the object side, and the right side is the image side. Note that Fig. 3, like Fig. 1, only configurations directly related to the description of this embodiment are extracted and shown, and configurations not directly related to the description of this embodiment are omitted.

[0026] The lens device 100b of this embodiment differs from the lens device 100 of the first embodiment having only one voice coil motor in that it has a first voice coil motor (first driving member) 20b and a second voice coil motor (second driving member) 20c as a driving unit. However, this embodiment is not limited to a configuration having two voice coil motors, and can also be applied to a configuration having three or more voice coil motors. In this embodiment, the two voice coil motors are a common motor, but this embodiment is not limited to this, and can also be applied to two motors with different characteristics and sizes. Note that other configurations and operations of the lens device 100b are common to the lens device 100, so their description will be omitted.

[0027] The first voice coil motor 20b has a coil 21b, a magnet 22b, and a yoke 23b, and is disposed outside the second holding frame 12 that holds the second lens group L2. Similarly, the second voice coil motor 20c has a coil 21c, a magnet 22c, and a yoke 23c, and is disposed outside the second holding frame 12 that holds the second lens group L2.

[0028] Also, the front end 201b of the first voice coil motor 20b (the first end (third end) of the first voice coil motor 20b closest to the object) is disposed at a position closer to the image side than the front end 121 (the second end (second end) of the second holding frame 12 closest to the object) of the second holding frame 12. Similarly, the front end 201c of the second voice coil motor 20c (the first end (fourth end) of the second voice coil motor 20c closest to the object) is disposed at a position closer to the image side than the front end 121 of the second holding frame 12.

[0029] In this embodiment, in the optical axis direction, a position P3 of the third end (front end 201b) of the first voice coil motor 20b closest to the object and a position P4 of the fourth end (front end 202c) of the second voice coil motor 20c closest to the object are different from each other. That is, the positions P3 and P4 do not coincide with each other in the optical axis direction.

[0030] In cases where the weight of the second lens group L2 is large, it is preferable to use multiple voice coil motors to drive the second holding frame 12 rather than using only one voice coil motor. Arranging multiple voice coil motors further increases the possibility of interference with other components on the object side and image side of the second holding frame 12 and other components outside (radially) the second holding frame 12. By shifting the positions of the multiple voice coil motors in the optical axis direction as in this embodiment, the degree of freedom in component arrangement can be improved.

[0031] Furthermore, according to this embodiment, the first voice coil motor 20b and the second voice coil motor 20c are arranged at different positions in the optical axis direction, so the balance of the Lorentz forces is shifted. Therefore, if the center of gravity of the second holding frame 12 is not on the optical axis OA (center) because the second holding frame 12 is not symmetrical, shifting the positions of the two voice coil motors enables well-balanced driving.

[0032] Next, an imaging device 200 including the lens device 100 (100a, 100b) of each embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic diagram of the imaging device 200.

[0033] In Fig. 4, 50 denotes a camera body, and 11 denotes the lens device 100 (100a, 100b) described in the first to third embodiments. 60 denotes an imaging element (photoelectric conversion element) such as a CMOS sensor or a CCD sensor that is built into the camera body 50 and receives an optical image formed by the optical system of the lens device 100 and photoelectrically converts it. The camera body 50 may be either a so-called single-lens reflex camera having a quick-turn mirror, or a so-called mirrorless camera having no quick-turn mirror. The lens device of each embodiment is applicable not only to digital still cameras, but also to other imaging devices such as video cameras.

[0034] According to each embodiment, a small-sized lens device and imaging device can be provided.

[0035] The disclosure of each embodiment includes the following configurations.

[0036] (Configuration 1) a plurality of lens groups arranged in order from the object side to the image side, the lens group including a first lens group, a second lens group, and a rear lens group; a first holding portion that holds the first lens group; a second holding portion that holds the second lens group and moves together with the second lens group in the optical axis direction; a drive unit that drives the second holding unit in the optical axis direction, During zooming from the wide-angle end to the telephoto end, the intervals between adjacent lens groups of the plurality of lens groups change, a first end of the drive unit closest to the object side in the optical axis direction is disposed at the same position as a second end of the second holding unit closest to the object side, or at a position closer to the image side than the second end. (Configuration 2) the driving unit is a voice coil motor, A coil provided in the second holding portion; 2. The lens device according to claim 1, further comprising a magnet and a yoke that form a magnetic field to move the coil. (Configuration 3) The lens device described in configuration 2, characterized in that when viewed in the optical axis direction from the object side to the image side, at least a portion of each of the coil, the magnet, and the yoke of the driving unit and at least a portion of the second holding unit overlap each other. (Configuration 4) The lens device described in any one of configurations 1 to 3, characterized in that when viewed in the optical axis direction from the object side to the image side, at least a portion of the drive portion and at least a portion of the first holding portion overlap each other. (Configuration 5) The drive unit has a first drive member and a second drive member, The lens device described in configuration 1 or 2, characterized in that, in the optical axis direction, a position of a third end of the first driving member closest to the object side and a position of a fourth end of the second driving member closest to the object side are different from each other. (Configuration 6) 6. The lens apparatus according to any one of configurations 1 to 5, wherein the first lens group does not move during zooming. (Configuration 7) 7. The lens apparatus according to any one of configurations 1 to 6, wherein the rear lens group includes at least a third lens group arranged on the image side of the second lens group. (Configuration 8) The lens device according to claim 2, characterized in that the length in the optical axis direction from the outermost end to the innermost end of the yoke in the radial direction (direction perpendicular to the optical axis direction) is shorter than the length in the optical axis direction from the end of the yoke closest to the object side to the end of the yoke closest to the image side. (Configuration 9) 9. The lens device according to claim 1, wherein the second holding portion is smaller than the first holding portion in a radial direction. (Configuration 10) 10. An imaging device comprising the lens device according to any one of configurations 1 to 9, and an imaging element.

[0037] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0038] L1 First lens group L2 Second lens group L3: 3rd lens group (rear lens group) 11 First holding frame (first holding portion) 12 Second holding frame (second holding portion) 20 Voice coil motor (drive unit) 100, 100a, 100b Lens device

Claims

1. a plurality of lens groups arranged in order from the object side to the image side, the lens group including a first lens group, a second lens group, and a rear lens group; a first holding portion that holds the first lens group; a second holding portion that holds the second lens group and moves together with the second lens group in the optical axis direction; a drive unit that drives the second holding unit in the optical axis direction, the driving unit is a voice coil motor having a first driving member including a first coil, a second driving member including a second coil, and a magnet and a yoke that form a magnetic field to move the first coil; a first end portion of the drive portion closest to the object side is disposed at the same position as a second end portion of the second holding portion closest to the object side, or at a position closer to the image side than the second end portion, in the optical axis direction; A lens device characterized in that the length in the optical axis direction from the outermost end to the innermost end of the yoke in the radial direction is shorter than the length in the optical axis direction from the end of the yoke closest to the object to the end of the yoke closest to the image.

2. 2. The lens device according to claim 1, wherein when viewed in the optical axis direction from the object side to the image side, at least a portion of each of the first coil, the magnet, and the yoke of the driving unit and at least a portion of the second holding unit overlap each other.

3. 2. The lens device according to claim 1, wherein at least a portion of the drive portion and at least a portion of the first holding portion overlap each other when viewed in the optical axis direction from the object side to the image side.

4. 2. The lens device according to claim 1, wherein a position of a third end of the first driving member closest to the object side and a position of a fourth end of the second driving member closest to the object side are different from each other in the optical axis direction.

5. 2. The lens apparatus according to claim 1, wherein the rear lens group includes at least a third lens group arranged on the image side of the second lens group.

6. 2. The lens device according to claim 1, wherein the second holding portion is smaller than the first holding portion in the radial direction.

7. An imaging device comprising: a lens device according to claim 1; and an imaging element.

Images