JP2000098444A - Light quantity adjusting device, and lens barrel and camera provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a lens barrel and to stably drive a diaphragm in the case of driving a diaphragm blade by a diaphragm driving part and a driving lever. SOLUTION: This device is equipped with a first driving lever 31 provided on the output shaft of an iris stepping motor 30 supported by a second moving ring 5 holding a part of a lens group, and a second driving lever 32 turnably supported by a rotary shaft 32a at the optimum position of the ring 5, and the top pin 31a of the lever 31 is fit in the long groove 32b of the lever 32, and a driving pin 32c provided on the lever 32 is fit in the long groove 7b of a pair of diaphragm blades 7, and the blade 7 is turned by the driving force of the motor 30 through the levers 31 and 32, so that its stop amount is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light amount adjusting device such as a diaphragm and a shutter in an image pickup device such as a video camera, a lens barrel including the amount adjusting device, and a camera.

[0002]

2. Description of the Related Art Conventionally, a blade driving lever in a light amount adjusting device is attached to a tip of an output shaft of a driving unit, and the blade is fitted to a fitting pin provided at the tip of the lever, thereby rotating the driving lever. Is changed to the rotation of the blade to adjust the amount of light reaching the imaging surface. At this time, the aperture driving unit and the driving lever are arranged so that the open end and the closed end of the lever are distributed near the line connecting the center of rotation of the blade, so that the operating torque and the straight line of the Hall output at the time of the galvanometer are arranged. The layout was optimized to satisfy the needs.

[0003]

However, in recent years, there has been a demand for downsizing of a photographing lens barrel used for a video camera or the like, and the arrangement of the aperture driving unit and the driving lever is the original optimal arrangement of the blade. If the open end and the closed end of the lever are arranged so as to be distributed at a position near the line connecting the rotation centers, it is difficult to reduce the size. There was a problem that it could not work.

The present invention has been made in view of the above-mentioned problems of the prior art,
It is an object of the present invention to provide a light amount adjusting device capable of appropriately driving an aperture even if the lens barrel is downsized, a lens barrel having the light amount adjusting device, and a camera.

[0005]

In order to achieve the above object, the present invention provides a first drive lever provided on an output shaft of a drive unit and a second drive lever having a different rotation center from the first drive lever. The diaphragm blade is driven via a lever.

[0006]

According to the first aspect of the present invention, a first drive lever provided on an output shaft of a drive unit, and a rotation center interlocked with the first drive lever and having a center of rotation of the drive unit. By having a second drive lever separate from the output shaft and an aperture blade member that is driven in conjunction with the second drive lever, the drive unit and the first drive lever cannot be arranged at optimal positions. However, since the second drive lever can be arranged at the optimum position, stable driving of the diaphragm blades can be achieved. According to the second aspect of the present invention, the aperture blade member driven in conjunction with the second drive lever is the aperture blade itself, so that even if the first drive lever cannot be arranged at the optimum position, Aperture blade drive is possible. The present invention as set forth in claim 3 is characterized in that the second
The aperture blade member driven in conjunction with the drive lever is a blade drive ring and the aperture blade driven by being fitted to the blade drive ring. The diaphragm blade can be driven. According to a fourth aspect of the present invention, the size of the lens barrel can be reduced by including the light amount adjusting device according to any one of the first to third aspects in the lens barrel. According to the fifth aspect of the present invention, the camera can be downsized by providing the lens barrel according to the fourth aspect in a camera.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will now be described with reference to FIGS.
Description will be made based on 0. 1 and 2 are cross-sectional views of main parts of a lens barrel for a camera having a light amount adjusting device according to the present embodiment, respectively. FIGS. 3 and 4 are cross-sectional views of main parts in a direction orthogonal to FIG. 5 and 6 are sectional views taken along lines AA and BB in FIG. 1, respectively, and FIG. 7 is a sectional view taken along line CC in FIG. In the drawing, reference numeral 1 denotes a first lens frame for holding a first lens unit L1 for zooming, 2 denotes a first moving ring for holding the first lens frame 1 in an inner diameter portion, 3 denotes a protective glass, and 4 denotes a protective glass. A protective glass frame 5 that holds the glass 3 and is held in front of the first moving ring 2 is a second moving ring that holds the second lens unit L2 for zooming. Reference numeral 6 denotes a substrate, which is attached to the front end of the second moving ring 5. Reference numeral 7 denotes an aperture blade, which is rotatably supported on the front surface of the substrate 6 by a rotation shaft 7a. Reference numeral 8 denotes a blade holding plate for holding the diaphragm blade 7, reference numeral 9 denotes a third moving ring for holding a third lens unit L3 for focusing, and reference numeral 10 denotes a first guide bar for guiding the first moving ring 2 in the optical axis direction. , 11 are second guide bars for preventing rotation of the first movable ring 2, 12 are third guide bars for guiding the second movable ring 5 in the optical axis direction, and 13 are for the second movable ring 5. The fourth guide bar 14 for preventing rotation is the third guide bar.
A fifth guide bar 15 for guiding the movable ring 9 in the optical axis direction is a fixed cylinder.

Reference numeral 16 denotes a CCD holder, and the guide bar 1
0 to 14, the fixed barrel 15, and a CCD 37 described later. Reference numeral 17 denotes a front frame which holds the guide bars 10 to 14 and is attached to the fixed cylinder 15. Reference numeral 18 denotes a cam ring which is fitted on the outer periphery of the fixed cylinder 15 and whose position in the optical axis direction is regulated by the front frame 17. Reference numeral 19 denotes a first spring, which urges the first movable ring 2 in the objective direction to remove play in the optical axis direction. Reference numeral 20 denotes a second spring, which urges the second movable ring 5 in the objective direction to remove play in the optical axis direction. 21 is the third
The third moving ring 9 is urged in the image forming direction by a spring to remove play in the optical axis direction. Reference numeral 22 denotes a first gear case.
It is attached to the D holder 16. 23 is a second gear case. Reference numeral 24 denotes a reduction gear composed of large and small gears, which is provided in the second gear case 23 and is held on an output shaft of a zoom stepping motor 26. A transmission gear 25 meshes with a small gear of the reduction gear 24.

Reference numeral 30 denotes an iris stepping motor driven by a diaphragm, which is attached to the second moving ring 5. Reference numeral 31 denotes a first drive lever for transmitting the throttle operating force. Reference numeral 32 denotes a second drive lever, which transmits a drive force from the first drive lever 31 to the aperture blade 7.

Here, the assembly structure of the aperture driving system will be described in detail with reference to FIGS. Iris stepping motor 3
Numeral 0 is fixed to the second movable ring 5 by screwing, and the mounting position is laid out at the position shown in the figure due to the relationship of other members forming the lens barrel. The iris stepping motor 3
The first drive lever 31 is attached to the output shaft
The drive lever 32 is rotatably fitted to a rotation center shaft 32 a provided on the second moving ring 5. The tip pin 31 a of the first drive lever 31 is fitted in the long groove 32 b of the second drive lever 32, and the rotation of the iris stepping motor 30 is rotated through the first drive lever 31 in angular phase, The center position is changed and transmitted to the second drive lever 32,
The tip pin 32c of the second drive lever 32 is fitted in the long groove 7a of the diaphragm blade 7 to rotate the diaphragm blade 7.

Reference numeral 33 denotes a focus stepping motor having a lead screw. 34 is a nut,
The driving force from the focus stepping motor 33 is transmitted to the third moving ring 9. A first photo interrupter 35 detects an initial position of the third moving ring 9 in the optical axis direction. Reference numeral 36 denotes a second photo interrupter, which is arranged so as to be able to block and transmit light in a direction perpendicular to the optical axis in order to detect an initial position of the cam ring 18 in the rotation direction. 37 is a CCD. Reference numeral 38 denotes a main flexible printed board, which includes the zoom stepping motor 26, the iris stepping motor 30, and the focus stepping motor 33.
And the first and second photointerrupters 35 and 36, respectively.

By the way, the aperture drive system is originally the first.
The drive lever and iris stepping motor are arranged so that the open end and the close end are distributed near the line connecting the center of rotation of the aperture blade.However, the operating torque, the linearity of the Hall output when the ruvanometer is Although the layout is optimal, in the present embodiment having the above configuration, it cannot be arranged at the optimal position due to the relationship between the other lens barrel members.
By arranging the drive lever 32, a stable operation torque and a configuration excellent in the linearity of the hall output are enabled.

In this embodiment, the stepping motor 30 is used as the diaphragm driving actuator. However, a galvano type actuator frequently used for a lens of a video camera may be used. The type is a two-aperture blade type in which two blades are driven simultaneously with a drive lever with a center of rotation, but a guillotine type in which two or three blades are driven linearly may be used. Not even. In the case of an iris diaphragm type that drives a plurality of blades, the plurality of diaphragm blades may be driven via a blade driving ring that is rotated by a driving lever.

[0014]

As described above, according to the first aspect of the present invention, the first drive lever provided on the output shaft of the drive unit, and the rotation center interlocked with the first drive lever are set. A drive actuator and its output are provided by having a second drive lever separate from the output shaft of the drive unit and an aperture blade member driven in conjunction with the second drive lever to reduce the size of the lens barrel layout. Even if the drive lever provided on the shaft cannot be placed at the optimum position, the second drive lever can be placed at the optimum position to stabilize the operating torque and to secure the linearity of the hall output, and to achieve stable aperture blades. Can be driven. According to a second aspect of the present invention, the aperture blade member driven in conjunction with the second drive lever is the aperture blade itself. Since the aperture blade member driven in conjunction with the blade drive ring and the aperture blade that is driven by being fitted to the blade drive ring, the same appropriate aperture blade drive can be performed.

According to a fourth aspect of the present invention, the size of the lens barrel can be reduced by providing the light amount adjusting device according to any one of the first to third aspects in the lens barrel. According to a fifth aspect of the present invention, the camera provided with the lens barrel according to the fourth aspect allows the camera to be downsized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a lens barrel having a light amount adjusting device according to an embodiment of the present invention when a lens is housed.

FIG. 2 is also a vertical sectional view at a different position.

FIG. 3 is a longitudinal sectional view in a section orthogonal to FIG. 1;

FIG. 4 is a vertical sectional view at a lens extension position.

FIG. 5 is a sectional view taken along line AA of FIG. 1;

FIG. 6 is a sectional view taken along line BB of FIG. 1;

FIG. 7 is a sectional view taken along line CC of FIG. 2;

FIG. 8 is an enlarged vertical sectional view of the second moving ring portion.

FIG. 9 is an enlarged front view of the throttle unit attached to the second moving ring.

FIG. 10 is a front view of a drive lever portion of the aperture portion.

[Explanation of symbols]

L1 first lens group, L2 second lens group, L3
3rd lens group, 1st first lens frame, 2nd first moving ring, 3rd protective glass, 4th protective glass frame, 5th second moving ring, 6, substrate, 7・ Aperture blade, 9 ・ ・ 3rd moving ring, 10, 11, 12, 13, 14 ・ ・ Guide bar,
16. CCD holder, 17 front frame, 18 cam ring, 19, 20, 21 spring, 26 zoom stepper motor, 30 iris stepper motor,
31 first drive lever, 31a pin, 32 second drive lever, 32a rotation center shaft, 32b long groove for fitting, 32c fitting pin, 33 focus focusing motor .

Claims (5)

[Claims] 1. A first drive lever provided on an output shaft of a drive unit, and a second drive lever interlocked with the first drive lever and having a center of rotation separate from the output shaft of the drive unit. And a diaphragm blade member driven in conjunction with the second drive lever. 2. The light amount adjusting device according to claim 1, wherein the diaphragm blade member driven in conjunction with the second drive lever is the diaphragm blade itself. 3. An aperture blade member driven in conjunction with said second drive lever is a blade drive ring and an aperture blade driven by being fitted to said blade drive ring. The light amount adjusting device according to the above. 4. A lens barrel comprising the light amount adjusting device according to claim 1. 5. A camera comprising the lens barrel according to claim 4.