JP2835048B2 - Zoom lens device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera zoom lens device, and more particularly to an inner focus type zoom lens device.

(Prior Art) Generally, as a lens of a camera having an autofocus function, a so-called front lens focus type in which a first group lens located at a tip of a lens barrel in a photographing optical system is moved to perform focusing, A so-called inner focus type in which focusing is performed by moving the second group lens or the third group lens is known. For example, in an inner focus type camera, a drive motor is provided in the camera body, and an interlocking shaft that is rotationally driven by the motor passes through the lens barrel from the camera body to the second or third group. It extends to near the lens. By driving the interlocking shaft while the gear attached to the interlocking shaft is meshed with the gear formed on the holding frame of the lens group, the lens group is moved to perform focusing.

In recent years, many zoom lenses having an autofocus function have been provided.

(Problems to be Solved by the Invention) However, when the above-described autofocus mechanism is applied to a zoom lens, the following problem occurs.

First, an interlocking shaft for transmitting the driving force of the motor provided on the camera body side must be provided in the lens barrel, so that the lens barrel becomes large and members provided in the lens barrel become large. In order to avoid interference with the interlocking shaft, various measures are required, and as a result, the configuration becomes complicated. In the zoom lens, each lens group including the focusing lens group moves in the optical axis direction according to zooming. Therefore, in order to hold the drive gear of the interlocking shaft and the gear portion formed on the holding frame of the focusing lens group in the engaged state even during the zooming operation, the interlocking shaft is lengthened, and the driving gear or the gear portion is increased. Needs to be increased in the optical axis direction. However, in this case, a larger installation space for the focusing mechanism must be provided in the lens barrel, and
At the time of zooming, the driving gear or the gear portion interferes with other lens groups, and it is difficult to perform a zooming operation properly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a compact zoom lens device capable of favorably performing zooming of a photographing optical system with a simple configuration.

(Means and Actions for Solving the Problems) In order to achieve the above object, a zoom lens device according to the present invention includes: a moving frame that is moved along the optical axis direction of a photographic optical system by a zooming operation; A holding frame holding a focusing lens group having a front lens group and a rear lens group, the holding frame being movably supported along the optical axis direction of the photographing optical system; and A shutter blade supported by the holding frame therebetween; a shutter driving mechanism supported by the moving frame on one side of the shutter blade to open and close the shutter blade; and supported by the moving frame on the other side of the shutter blade. A focusing mechanism for moving the holding frame along the optical axis direction; and a shutter driving mechanism supported by the moving frame and the focusing mechanism. And a motor for selectively driving the mechanism.

According to the above configuration, the focusing device and the shutter driving mechanism are mounted on the moving frame and located near the focusing lens group. Therefore, there is no need to insert the interlocking shaft into the lens barrel as in the related art, and the apparatus can be reduced in size and the configuration can be simplified. Further, since these mechanisms are supported by the moving frame and move integrally with the focusing lens group during the zooming operation, there is no need to provide a long drive gear or gear portion as in the related art. Therefore, the zooming operation can be favorably performed without interference with other lens groups, and the focusing mechanism can be easily reduced in size. Further, by making effective use of the space on both sides of the shutter blade, it is possible to further reduce the size of the entire apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a lens shutter camera provided with an inner focus type zoom lens device according to one embodiment of the present invention. This camera includes a camera body 10,
The zoom lens device 11 protrudes forward from substantially the center of the front surface of the camera body. Further, the camera body 10 has a grip portion 14 protruding forward from the front side along the zoom lens device 11. Inside the grip unit 14, a finder mechanism 16, a strobe mechanism 18, and a zoom lens
A drive mechanism 20 for zooming the photographing optical system 11 is provided, and is located close to the side of the zoom lens device. Further, a battery chamber (not shown) containing a battery is formed in the grip portion 14.

As shown in FIG. 1, the zoom lens device 11 includes a lens barrel 12. The lens barrel 12 has a cylindrical fixed frame 22.
A cylindrical cam ring 24 is rotatably fitted around the outer periphery of the fixed frame. A screw portion 23 is formed on the inner peripheral surface of the distal end portion of the cam ring 24, and a focus adjustment ring 26 is screwed into the screw portion. By rotating the adjustment ring 26, the cam ring 24 can be slightly moved in the axial direction.
A holding ring 27 is attached to the outer periphery of the distal end of the fixed frame 22 and is in contact with the adjustment ring 26. A cylindrical zoom frame 28 is inserted into the fixed frame 22 so as to be movable in the axial direction. Three roller pins are provided on the outer periphery of the zoom frame 28.
29 (only one is illustrated), each roller pin passes through a straight groove 22a formed in the fixed frame 22 and is inserted into a first cam groove 24a formed in the cam ring 24. Have been. The straight groove 22a extends along the axial direction of the fixed frame 22, and the cam groove 24a is formed in a spiral shape. Therefore, by rotating the cam ring 24, the zoom frame 28 moves linearly along its axial direction. Further, a light-shielding cloth 30 is attached to the inner peripheral surface of the distal end portion of the fixed frame so that light does not enter the gap between the fixed frame 22 and the zoom frame 28 from outside,
It is in sliding contact with the outer peripheral surface of the zoom frame.

In the zoom frame 28, first to third group lenses 31, 32, and 33 constituting a photographing optical system are arranged. More specifically, the first group lens 31 is supported in the zoom frame by a first group frame 34 screwed into the tip of the zoom frame 28. A substantially cylindrical moving frame 36 is fitted to an intermediate portion in the zoom frame 28 so as to be movable in the axial direction. 3 in the moving frame 36
Two roller pins 37 (only one is shown) protrude, and each roller pin 37 penetrates a linear groove 38 formed in the zoom frame 28 and a linear groove 22a formed in the fixed frame 22,
It is inserted into a spiral second cam groove 24b formed in the cam ring 24. Therefore, by rotating the cam ring 24, the moving frame 36 moves in the zoom frame 28 along the axial direction. A focusing guide shaft 40 is fixed to the moving frame 36, and extends in parallel with the axis of the zoom frame 28. Note that the right end of the guide shaft 40 is immovably fixed to the moving frame 36, and the left end is supported by a spring washer 41 so as to be finely movable. Therefore, by adjusting the position of the left end of the guide shaft 40, the parallelism of the guide shaft to the optical axis of the photographing optical system can be adjusted. The holding frame 42 holding the second group lens 32 is supported by the guide shaft 40 so as to be movable along the axial direction of the zoom frame 28. The second lens group constitutes the focusing lens group in the present invention, and has a front lens group 32a and a rear lens group 32b.
The holding frame 42 is a front holding frame 42a holding the front lens group 32a.
And a rear holding frame 42b that holds the rear lens group 32b. A focusing spring 45 is wound around the guide shaft 40, and the spring is used by the front holding frame 42a and the rear holding frame 42b.
Is biased backwards. Thereby, the rear holding frame
The pin 44 projecting from 42b is pressed against a cam surface of a focusing cam 47 of a focusing mechanism 58 described later. Then, by rotating the focusing cam 47, the front holding frame 42a and the rear holding frame 42b are moved forward by the cam 47 against the urging force of the spring 45, and as a result, the imaging optical system is focused. Further, between the front holding frame 42a and the rear holding frame 42b, a shutter blade 48 also serving as an aperture is provided.
The shutter blades are opened and closed by a shutter driving mechanism 60 described later.

A third group frame 50 is fitted into the base end of the zoom frame 28 so as to be movable in the axial direction of the zoom frame. Third group frame 50
Are provided with three roller pins 51 (only one is shown), and each roller pin penetrates a linear groove 52 formed in the zoom frame 28 and a linear groove 22a formed in the fixed frame, It is inserted into a spiral third cam groove 24c formed on the cam ring 24. Therefore, by rotating the cam ring 24, the third group frame 50 moves in the zoom frame 28 along the axial direction. In addition, the third group lens is provided on the inner periphery of the third group frame 50.
A holding frame 54 holding 33 is fitted and fixed. And
By adjusting the relative position between the third group frame 50 and the holding frame 54 by a known mechanism (not shown), focus movement during zooming can be corrected.

The lens barrel 12 configured as described above is fixed to the camera body by screwing the flange 22b formed at the base end of the fixed frame 22 to the camera body 10.

As shown in FIGS. 1 and 3, on the outer peripheral surface of the cam ring 24, an arc-shaped interlocking plate 56 is fixed by screws.
On an outer surface of the interlocking plate 56, a gear portion 57 extending on an arc concentric with the cam ring 24 is formed. And the cam ring 24
A drive mechanism 20 provided on the side of the lens barrel 12 is used to drive a gear unit.
It is rotated by the driving force transmitted through 57. Then, when the cam ring 24 is rotated, the photographing optical system operates in conjunction with this to move the wide motor position (FIG. 4A) and the telemode position (
4B) and the macro mode position (FIG. 4C). When switching from the wide mode to the tele mode, the first to third lens units 31, 32 and 33 are moved forward, and when switching from the tele mode to the macro mode, the first and second lens units are held in a stopped state. Then, only the third lens group is moved backward. In FIG. 4, reference numeral 43 indicates a film surface.

As shown in FIG. 3, the finder mechanism 16 and the flash mechanism 18 are provided on the side of the lens barrel 12, and are zoomed by the interlocking plate 56 in conjunction with the rotation of the cam ring 24.

On the other hand, as described above, in the zoom lens device 11, focusing of the imaging optical system is performed by moving the second group lens 32 as a focusing lens group in the optical axis direction, and is a so-called inner focus type. Hereinafter, the focusing mechanism 58 and the shutter driving mechanism 60 of the zoom lens device 11 will be described in detail.

As shown in FIG. 1, the focusing mechanism 58 and the shutter driving mechanism 60 are attached to the moving frame 36, and are disposed on the third group lens 33 side and the first group lens 31 side of the shutter blade 48, respectively. Focusing mechanism 58
Is disposed between the moving frame 36 and the rear holding frame 42b, and the shutter driving mechanism 60 is disposed between the moving frame and the front holding frame 42a.

As shown in FIG. 5, the moving frame 36 includes a substantially cylindrical main body 62 supported on the zoom frame 28 by roller pins 37, and an annular focusing frame 64 attached to the third group lens 33 side of the main body. It is composed of a shutter frame 66 attached to the first group lens 31 side of the main body, and an annular cover 67 provided facing the shutter frame. A focusing mechanism 58 is mainly attached to the focusing frame 64, and a shutter driving mechanism 60 is attached to the shutter frame 66.

The focusing guide shaft 40 has a main body 62 and a shutter frame 66
The holding frame 42 is movably supported by the guide shaft. The holding frame 42 is also guided by a pair of guide posts 62a projecting from the main body 62.

The focusing mechanism 58 has a focusing cam 47 attached to a focusing frame 64 so as to be rotatable around the optical axis of the photographing optical system, and a pin formed on the cam surface 47a of the cam 47 and the rear holding frame 42b. 44 are in contact. The focusing mechanism 58 includes a focusing drive gear train 68 attached to the focusing frame 64 and meshing with the cam 47, and a timing switch 70 fixed to the focusing frame and in contact with the outer peripheral surface of the cam 47. Have. The switch 70 detects the initial position of the cam 47 at the start of focusing, and controls the amount of rotation of the cam 47 according to a signal from a photo interrupter described later. Further, the focusing frame 64 is provided with a shutter drive gear train 71 and a planetary clutch 72 located between the gear trains 68 and 71.

A motor 74 that operates as a common drive source for the focusing mechanism 58 and the shutter drive mechanism 60 is fixed to the main body 62. The rotating shaft 74a of the motor 74 extends toward the focusing frame 64, and the drive gear 75 and the above-mentioned planetary clutch 72 are attached to this rotating shaft. As shown in FIG. 6, the planetary clutch 72 is
a planetary lever 76 rotatably mounted with a predetermined friction against a, and a pair of planetary gears rotatably supported by the planetary lever and meshed with the drive gear 75, respectively.
77a and 77b. Arrow A of the rotating shaft 74a of the motor 74
When rotated forward in the direction, the planetary lever 76 also rotates in the direction of arrow A, and the planetary gear 77a meshes with the focusing drive gear train 68. Thereby, the focusing cam 47 is rotated to perform focusing. When the rotation shaft 74a is rotated in the reverse direction, the planet gear 77b meshes with the shutter drive gear train 71, and drives the gear train 71. Note that a comb gear 78 is fixed to the tip of the rotating shaft 74a, and a photo interrupter 79 is provided to face the comb gear. The photointerrupter 79 counts the pulse of the rotation of the comb gear 78, that is, the rotation of the motor 74, and controls the rotation of the motor by a control circuit (not shown).

On the other hand, as shown in FIGS. 5 and 7, the shutter drive mechanism 60 attached to the shutter frame 66 has an idler gear 80, which is connected to a shutter drive gear train 71 via a connection gear 81. ing. The idler gear 80 meshes with an exposure adjustment cam gear 82 attached to the shutter frame 66. On the upper surface of the cam gear 82, a pin 82a protrudes eccentrically from the rotation center of the cam gear, and on the lower surface, a cam surface 82b is formed. A terminal of an exposure adjustment switch 83 fixed to the shutter frame 66 is engaged with the cam surface 82b. The shutter drive mechanism 60 has a drive arm 84, and an intermediate portion of the drive arm is rotatably supported on the shutter frame 66 by a shaft 84a. An iron piece 85 is fixed to the left end of the drive arm 84, and is positioned to face an electromagnet 86 fixed to the shutter frame 66. At the right end of the drive arm 84, an open / close arm
An intermediate portion of 88 is rotatably supported by a shaft 88a.
The drive arm 84 is urged clockwise around the axis 84a by a torsion spring 87, and the open / close arm 88 is rotated by a torsion spring 89.
It is biased clockwise around 88a. Open / close arm 88
A cam surface 88b that can contact the pin 82a of the exposure adjustment gear 82 is formed on the right end of the exposure adjustment gear 82. An opening / closing pin 90 is projected from the left end of the opening / closing arm 88, and extends through the long hole 66a formed in the shutter frame 66 toward the main body 62 of the moving frame 36. Further, a regulating lever 91 for adjusting the amount of movement of the opening / closing pin 90 is rotatably attached to the shutter frame 66. The regulating lever 91 is urged counterclockwise by a spring 92, and the arm 91a of the regulating lever is pressed against the opening regulating cam 28a fixed to the zoom frame 28. Further, the other arm 91b of the regulating lever 91 can enter the moving path of the opening / closing pin 90 with the rotation of the lever.

The shutter blades 48 opened and closed by the shutter drive mechanism 60, as shown in FIG. 5, FIG. 7, and FIG.
It is composed of a pair of blade members 48a, 48b. These blade members 48a, 48b are disposed between the flange 43a of the front holding frame 42a and the flange 43b of the rear holding frame 42b,
A pin 94 formed on the flange 43b is rotatably supported between a closed position shown in FIG. 8 and an open position shown in FIG. In addition, the blade members 48a and 48b
6a and 96b, and these long holes are formed so that a part thereof always overlaps with each other. And the shutter drive mechanism
The 60 opening / closing pins 90 are inserted into the long holes 96a, 96b of the blade members 48a, 48b through the through holes 97 formed in the flange 43a of the front holding frame 42a. Therefore, the blade members 48a and 48b are opened and closed according to the movement of the opening and closing pins 90.

Next, the focusing mechanism 58 configured as described above
The operation of the shutter drive mechanism 60 will be described.

When the shutter button provided on the camera body 10 is pressed after the zooming of the photographing optical system is completed, the motor 74 rotates forward and the planetary gear 77a of the planetary clutch 72 meshes with the focusing drive gear train 68. Thereby, the focusing cam 47 is rotated via the focusing drive gear train 68, and the rear holding frame 42b pressed against the cam surface 47a of the cam 47
The pin 44 moves following the displacement of the cam surface. As a result, the second group lens 32 of the photographing optical system is moved along with the holding frame 42 along the optical axis direction to perform focusing. At this time, the switch 70 for detecting the initial position of the focusing cam 47 is turned off at the same time as the rotation of the cam 47 is started, and in synchronization with this, the photointerrupter 79 starts counting drive pulses. When the count reaches a predetermined value, that is, when the rotation amount of the focusing cam 47 reaches a predetermined value, the motor 74 is stopped and the focusing is completed.

Subsequently, the motor 74 starts to rotate in reverse, and the shutter drive mechanism
The drive of 60 is started. That is, the reverse rotation of the motor 74 causes the planetary gear 77b of the planetary clutch 72 to mesh with and drive the shutter drive gear train 71. This driving force is transmitted to the idler gear 80 via the connecting gear 81, and as a result, the exposure adjusting gear 82 is rotated in the direction of arrow B in FIG. At the beginning of the rotation of the gear 82, the opening / closing arm 88 has a cam surface.
The drive arm 84 is pressed by the pin 82a that abuts on 88b, and is turned counterclockwise against the urging force of the torsion spring 87. Thereby, as shown in FIG. 7, the iron piece 85 of the drive arm 84 is attracted to the electromagnet 86, and the charging of the shutter drive mechanism 60 ends. In this state, the opening / closing arm 88
The opening / closing pin 90 of the shutter 48 is located at the lower end of the slot 66a.
Is closed.

When the exposure adjusting gear 82 is further rotated, the pin 82a moves in a direction away from the opening / closing arm 88, and the opening / closing arm is rotated clockwise by the urging force of the torsion spring 89 and moves following the pin 82a. As a result, the opening / closing pin of the opening / closing arm 88
90 moves upward in the long hole 66a and gradually opens the shutter blade 48. Here, the terminal of the exposure adjustment switch 83 falls into a groove 82c formed on the cam surface 82b of the exposure adjustment gear 82, and once the switch 83 is turned on, the shutter blade 48 starts to open, and at the same time, the terminal Switch in contact with 8
Switch 3 off. Then, when the switch 83 is turned off, a shutter control rotation (not shown) is activated, and an appropriate shutter opening time is determined. When the proper opening time is reached, that is, when the proper exposure is reached, the driving of the motor 74 is stopped, and the electromagnet 86 is switched off, so that the attraction force of the iron piece 85 is removed. Thus, the drive arm 84 is rotated clockwise together with the opening / closing arm 88 by the torsion spring 87. Therefore, the opening / closing pin 90 of the opening / closing arm 88 moves down to the lower end of the elongated hole 66a, and in conjunction with this, the shutter blade 48 is closed.

When the photographing optical system is set to the wide mode (FIG. 4A), the regulating lever 91 is pressed by the opening regulating cam 28a provided on the zoom frame and rotated clockwise. Accordingly, the arm 91b of the regulating lever 91 projects into the movement path of the opening / closing pin 90. Therefore, the movement amount of the opening / closing pin 90 is regulated by the regulating lever 91, and the opening diameter of the shutter blade 48 is regulated.

According to the zoom lens device configured as described above,
The following advantages can be obtained.

That is, the focusing mechanism 58 and the shutter mechanism
Numeral 60 is attached to the moving frame 36, and is located near the second group lens 32 as a focusing lens group. Therefore, it is not necessary to insert the interlocking shaft into the lens barrel 12 as in the related art, and the device can be reduced in size and the configuration can be simplified. These mechanisms are supported by the moving frame 36 and move integrally with the focusing lens group during the zooming operation. Therefore, the focusing mechanism and the focusing lens group can be always maintained in the engaged state without providing a long drive gear or a gear portion as in the related art. Therefore, the zooming operation can be favorably performed without interference with other lens groups, and the focusing mechanism can be easily reduced in size. Further, a focusing mechanism 58 and a shutter driving mechanism 60 are provided on both sides of the shutter blade.
By disposing, the space on both sides of the shutter blade can be effectively used, and a single motor 74 attached to the moving frame 36 is shared as a drive source of the focusing mechanism 58 and the shutter drive mechanism 60. Therefore, the size of the entire apparatus can be further reduced.

In addition, since the second group lens 32 is supported by one focusing guide shaft 40 whose inclination can be adjusted, the inclination of the second group lens with respect to the other lens groups can be easily adjusted. Furthermore, the aperture diameter of the shutter blade 48, that is, the aperture can be adjusted according to the zooming mode of the photographing optical system by the regulating lever 91 that operates in conjunction with the aperture regulating cam 28a provided on the zoom frame. As a result, It is possible to reduce a difference between F values in each zooming mode of the photographing optical system.

In the case of the inner focus type zoom lens device, the moving amount of the focusing lens group at the time of focusing is smaller than that of the front focus type, so that the focusing speed can be increased and the focusing mechanism can be downsized. it can.

(Effects of the Invention) As described in detail above, the zoom lens device of the present invention includes: a moving frame that is moved along the optical axis direction of the photographing optical system by a zooming operation; Along with being supported movably along the axial direction,
A holding frame holding a focusing lens group having a front lens group and a rear lens group; shutter blades supported by the holding frame between the front lens group and the rear lens group; A shutter driving mechanism supported by the moving frame to open and close the shutter blades; a focusing mechanism supported by the moving frame at the other side of the shutter blades and moving the holding frame along the optical axis direction; A motor that is supported by the moving frame and selectively drives the shutter driving mechanism and the focusing mechanism.

Therefore, it is possible to provide a compact zoom lens device that can favorably perform zooming of the photographing optical system with a simple configuration.

[Brief description of the drawings]

1 to 9 show a zoom lens device according to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the zoom lens device, and FIG. 2 shows an entire camera provided with the zoom lens device. FIG. 3 is a perspective view, FIG. 3 is a plan view of the zoom lens device, FIGS. 4A to 4C are diagrams showing different operation modes of the photographing optical system, and FIG. FIG. 6 is a perspective view showing a configuration around a motor, FIG. 7 is a front view of a shutter drive mechanism, and FIGS. 8 and 9 are front views showing a closed state and an opened state of shutter blades, respectively. is there. 12 Lens barrel, 22 Fixed frame, 28 Zoom frame, 31
... First group lens (photographing optical system), 32... Second group lens (photographing optical system), 32a... Front lens group, 32b... Rear lens group, 33. ), 36: Moving frame, 40: Focusing guide shaft, 42: Holding frame, 48
… Shutter blade, 58… Focusing mechanism, 60…
… Shutter drive mechanism, 74 …… Motor.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuo Yamazaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside the Olympus Optical Industrial Co., Ltd. (72) Inventor Hitoshi Yagi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. (56) References JP-A-63-2030 (JP, A) JP-A-60-163014 (JP, A) Jpn. Sho 62-146116 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) G02B 7/10

Claims (1)

(57) [Claims] A moving frame which is moved along a direction of an optical axis of a photographing optical system by a zooming operation; and is supported by the moving frame so as to be movable along a direction of an optical axis of the photographing optical system. A holding frame holding a focusing lens group having a lens group and a rear lens group; a shutter blade supported by the holding frame between the front lens group and the rear lens group; A shutter driving mechanism supported by a moving frame to open and close the shutter blade; a focusing mechanism supported by the moving frame on the other side of the shutter blade to move the holding frame along the optical axis direction; And a motor supported by the frame and selectively driving the shutter driving mechanism and the focusing mechanism. Location.