JPH11142907A - Diaphragm mechanism for lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diaphragm mechanism for a lens barrel capable of miniaturizing a video camera. SOLUTION: As for the diaphragm mechanism 20 for the zoom lens barrel 1, a 1st work pin 23b and a 2nd work pin 23c are installed at both ends of a swing arm 23 swinging around a motor shaft 22a, and either one plate 24 is driven by the 1st work pin 23b and the other plate 25 is driven by the 2nd work pin 23, the 2nd work pin 23c is offset from a straight line linking between the 1st work pin 23b and the motor shaft 22a toward the lenses 6 to 9. Thus, even in the case of mounting the diaphragm mechanism on the zoom lens barrel with inclination, the corner part of the housing is prevented from projecting from the outer periphery of the zoom lens barrel, so that the diaphragm mechanism is mounted on the zoom lens barrel without projecting outwards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a diaphragm mechanism of a lens barrel.

[0002]

2. Description of the Related Art FIG. 6 is an exploded perspective view of a conventional aperture mechanism of a zoom lens barrel. Conventional aperture mechanism 1 for lens barrel
Reference numeral 00 denotes a housing 101, a lower blade 102 slidably mounted on the housing 101, and a lower blade 1
02; an upper blade 103 slidably mounted on the upper blade 02; an arm 104 for sliding the blades 102 and 103;
A motor 105 for driving the arm 104 and the lower blade 1
02 and a cover 106 that covers the upper blade 103.

[0003] In detail, the housing 101 includes guide bosses 101b provided on a base surface 101a (a plurality of bosses are shown; the same applies hereinafter), an outer peripheral portion 101c provided on the outer periphery of the base surface 101a, and this outer periphery. .. Provided in the portion 101c and the opening 101 provided in the base surface 101a.
e. The lower blade 102 has a notch 102a,
Slide grooves 102b fitted into the guide bosses 101b ...
And an elongated hole 102c fitted to a pin 104b provided on the arm 104. The upper blade 103 has the notch 10
3a and a slide groove 103 fitted to the guide boss 101b
and a long hole 103c fitted in a pin 104c provided on the arm 104.

[0004] The arm 104 is a flat plate-shaped arm. A mounting portion 104a for fitting to the motor 105 is provided at the center of the arm 104, and an elongated hole 1 is provided at one end of the arm 104.
A pin 104b that fits into the long hole 103c is provided at the other end of the arm 104. The cover 106 includes a base surface 106a, an opening 106b opened in the base surface 106a, a stepped portion 106c provided in the base surface 106a, and a slide portion 106d for slidably pressing the lower blade 102 and the upper blade 103. 106d, 106e, 106e and a claw portion 106f fitted to the fitting portion 101d of the housing 101.
Consists of

That is, the aperture mechanism 100 is provided with the motor 10
5, the lower blade 102 and the upper blade 103 are relatively slid, and the notch 10
The light transmission area of the diaphragm 107 formed by the cutout 2a and the notch 103a is varied.

FIG. 7 is a front view of a conventional aperture mechanism of a lens barrel, and shows a state where the aperture mechanism is assembled to a zoom lens barrel. Generally, a zoom lens barrel used for a video camera or the like forms an image of an object on an image sensor such as a CCD (Charge Coupled Device) by a front lens group, a variator lens group, a fixed master lens, and a moving master lens group. The image pickup device is configured to photoelectrically convert the subject image, and the diaphragm mechanism 100 is incorporated between the variator lens group and the fixed master lens. Reference numerals 111 and 112 denote guide shafts that support the lens groups, 113 denotes a main lens barrel, and 114 denotes a sub lens barrel.

[0007]

In recent years, the size of video cameras has been steadily reduced. Therefore, it is necessary to downsize the zoom lens barrel, which is a component of the optical system of the video camera, while maintaining the performance. The guide shafts 111 and 112 that support the lens groups are disposed one each on the left and right sides of the stop 107, but the guide shafts 111 and 112
As shown in FIG. 7, one guide shaft 111 is raised and the other guide shaft 1
There is an attempt to reduce the horizontal interval H by lowering the H.12. At this time, when the stop mechanism 100 is to be mounted along the longitudinal axis of the main lens barrel 113 as indicated by a two-dot chain line, the stop mechanism 1
00 hits the guide shaft 111 and cannot be mounted. In order to avoid this, it is necessary to mount the diaphragm mechanism 100 obliquely to the zoom lens barrel as shown by the solid line.

However, in the above structure, when the diaphragm mechanism 100 is mounted obliquely with respect to the zoom lens barrel, the housing 101 of the diaphragm mechanism 100 projects from the outer periphery of the sub-barrel 114 by a dimension L. If the zoom lens barrel is incorporated in the video camera, the overhanging dimension L becomes a dead space, so that the overall size of the video camera cannot be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an aperture mechanism for a lens barrel that can reduce the size of a video camera.

[0010]

According to a first aspect of the present invention, two plates provided with notches for transmitting light are mounted on a housing so as to overlap with each other. An aperture mechanism for a lens barrel that is mounted at a fixed angle to the axis and changes the light transmission area by sliding the plate relatively, and a first arm is provided at both ends of a swing arm that swings about a motor axis. In a diaphragm mechanism of a lens barrel in which an operation point and a second operation point are provided, one plate is driven at the first operation point, and the other plate is driven at the second operation point, a first operation point and a motor shaft are provided. The second action point is offset to the lens side from the straight line connecting.

The housing of the aperture mechanism is mounted at a certain angle with respect to the longitudinal axis of the lens barrel. At this time, the second working point is offset toward the lens side from the straight line connecting the first working point and the motor shaft, and the corner of the housing is retracted.
The housing corner is prevented from protruding from the outer periphery of the lens barrel.

According to a second aspect of the present invention, two plates provided with cutouts for transmitting light are mounted on the housing so as to overlap with each other, and the housing is mounted at a predetermined angle with respect to the longitudinal axis of the lens barrel. An aperture mechanism for a lens barrel that changes a light transmission area by relatively sliding, wherein a first operating point and a second operating point are provided at both ends of a swing arm that swings about a motor axis. In a diaphragm mechanism of a lens barrel in which one plate is driven at a point and the other plate is driven at a second operation point, a first operation point, a motor shaft and a second operation point are arranged in a straight line on a common line. , First
The moving range of the second action point is symmetrical with respect to a straight line parallel to the horizontal axis of the lens barrel.

The housing of the diaphragm mechanism is mounted at a certain angle with respect to the longitudinal axis of the lens barrel. At this time, the first working point, the motor shaft, and the second working point are arranged in a straight line on a common line, and the moving range of the first and second working points is symmetrical with respect to a straight line parallel to the horizontal axis of the lens barrel. The corners of the housing are prevented from protruding from the outer periphery of the lens barrel.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals. FIG. 1 is a sectional view of a zoom lens barrel according to the present invention, showing main components. A zoom lens barrel 1 as a lens barrel includes a main barrel 2, a sub-barrel 3 fitted to the main barrel 2, a pair of guide shafts 4, 5 attached to the main barrel 2, A front lens group 6 as a lens attached to the lens barrel 2, a variator lens group 7 as a lens slidably attached to the guide shafts 4, 5 via a support member (not shown), and A fixed master lens 8 as a lens attached via a support member (not shown), a movable master lens group 9 as a lens slidably attached to the guide shafts 4 and 5 via a support member (not shown), and a main lens barrel 2 and a C filter attached to the main lens barrel 2 via an elastic member 12.
It comprises a CD (Charge Coupled Device) 13, a motor 14 for slidingly moving the variator lens group 7, a motor 15 for slidingly moving the movable master lens group 9, and an aperture mechanism 20 inserted from the sub-lens barrel 6 side. C indicated by a two-dot chain line indicates a video camera body.

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 and shows a cross section of the zoom lens barrel 1 according to the present invention. The guide shafts 4 and 5 indicate that they are arranged obliquely with respect to the horizontal axis X of the main lens barrel 2. The guide shaft 4 is fixed to the fixing groove 2 of the main lens barrel 2.
a guide shaft 5 is inserted into the fixing groove 2 b of the main lens barrel 2, and is supported by the holding portion 3 a of the sub lens barrel 3.
Indicates that the supporting member 3b is supported by the holding portion 3b. The aperture mechanism 20
This shows that the zoom lens barrel 1 is mounted at an inclination angle θ with respect to the longitudinal axis Y.

FIG. 3 is an exploded perspective view of the aperture mechanism of the zoom lens barrel according to the first embodiment of the present invention. Aperture mechanism 20
Are a housing 21, a motor 22 mounted on the housing 21, a swing arm 23 rotatably mounted on a motor shaft 22a of the motor 22, a lower plate 24 as two plates slid by the swing arm 23, and The upper plate 25 and these plates 24,
And a cover 26 that covers the cover 25. That is, the diaphragm mechanism 20 rotates the swing arm 23 with the motor 22 to relatively slide the lower plate 24 and the upper plate 25, thereby changing the light transmission area formed by the lower plate 24 and the upper plate 25. It is.

Specifically, the housing 21 is provided on the base surface 2.
1a, a motor mounting portion 21b is provided, an opening 21c is provided in a base surface 21a, and a guide boss 21d is provided in the base surface 21a.
..., an outer peripheral portion 21e is provided on the base surface 21a, and a tapered portion 21f is provided on a part of the outer peripheral portion 21e.
1e are provided with fitting portions 21g of the cover 26. 21h is a corner. The swing arm 23 is a flat arm and has a motor shaft 2
2a, a first operating pin 2 as a first operating point fitted to the lower plate 24 at one end.
3b, and a second working pin 23c as a second working point fitted to the upper plate 25 at the other end.

The lower plate 24 is a flat plate having a notch 24a formed on the outer periphery thereof, and a slide groove 24b fitted into the guide boss 21d.
An elongated hole 24c to be fitted into 3b is formed. The upper plate 25 is a flat plate having a notch 25a formed on the outer periphery thereof, a slide groove 25b fitted to the guide boss 21d, and a long hole 25c fitted to the second working pin 23c. It is formed. The cover 26 has an opening 26b in the base surface 26a, a step 26c in the base surface 26a, and a convex slide portion 26d for pressing the lower plate 24 and the upper plate 25 slidably.
26d, 26e, and 26e are provided, and claw portions 26f to be attached to the fitting portion 21g of the housing 21 are provided.

The operation of the above-described aperture mechanism of the zoom lens will be described with reference to FIG. FIGS. 4A and 4B are explanatory views of the operation of the aperture mechanism of the zoom lens barrel according to the first embodiment of the present invention, wherein FIG. 4A shows a state in which the aperture mechanism is closed, and FIG.
Indicates a state where the aperture mechanism is open. 2A, the diaphragm mechanism 20 is attached at a predetermined angle θ with respect to the longitudinal axis Y of the zoom lens barrel 1. At this time, the swing arm 23
The second working pin 23c is offset from the straight line A connecting the first working pin 23b and the motor shaft 22a toward the lenses 6 to 9 by a certain angle θ. The angle of the tapered portion 21f of the housing 21 is also set to a fixed angle θ. Therefore, even if the aperture mechanism 20 is attached to the zoom lens barrel 1 at an angle, the corner 21 h of the housing 21 does not protrude from the outer periphery of the zoom lens barrel 1, and the aperture mechanism 20 does not protrude from the zoom lens barrel 1. It can be installed with.

The swing arm 2 around the motor shaft 22a
3 is swung as indicated by the arrow, the lower plate 24 is slid as indicated by the arrow, and the upper plate 25 is slid as indicated by the arrow to open the aperture mechanism 20. As shown in (b), even when the aperture mechanism 20 is in the open state, the first working pin 2
The upper plate 25 and the swing arm 23 do not fly out of the housing 21 because the second working pin 23c is offset by a fixed angle θ toward the lenses 6 to 9 from the straight line A connecting the motor shaft 22a to the motor shaft 22a.

FIG. 5 is a front view of a diaphragm mechanism of a zoom lens barrel according to a second embodiment of the present invention. The aperture mechanism 30 is
It has substantially the same configuration as the diaphragm mechanism 20 (see FIG. 3) shown in the first embodiment, and includes a housing 31, a motor 32 mounted on the housing 31, and a swing arm rotatably mounted on a motor shaft 32a of the motor 32. 33, a lower plate 34 and an upper plate 35 as two plates to be slid by the swing arm 33, and a cover 36 covering these plates 34, 35. Note that 31
h is a corner of the housing 31, 33a is a swing arm 3.
3 is an attachment portion, 33b is a first working pin as a first working point, 33c is a second working pin as a second working point, 34a
Is a cutout of the lower plate 34, and 35a is a cutout of the lower plate 35.

The diaphragm mechanism 30 is mounted at an inclination angle θ with respect to the longitudinal axis Y of the zoom lens barrel 1. In addition, the aperture mechanism 30 arranges the first working pin 33b, the motor shaft 32a, and the second working pin 33c in a straight line on the common line B,
The movement range 2α of the second action pins 33b and 33c is symmetrical with respect to a straight line C parallel to the horizontal axis X of the zoom lens barrel 1. Accordingly, the corner 31h of the housing 31 does not protrude from the outer periphery of the zoom lens barrel 1, and the housing 31 can be mounted on the zoom lens barrel 1 without projecting the aperture mechanism 20.

In the first and second embodiments, the aperture mechanism of the zoom lens barrel has been described. However, the present invention can be applied to a fixed focus lens barrel.

[0024]

According to the present invention, the following effects are exhibited by the above configuration. In the first aspect, the second action point is offset toward the lens from a straight line connecting the first action point and the motor shaft.
Even when the diaphragm mechanism is attached to the zoom lens barrel at an angle, the corners of the housing do not protrude from the outer periphery of the zoom lens barrel, and can be mounted on the zoom lens barrel without projecting the diaphragm mechanism.

According to a second aspect, the first working point, the motor shaft and the second working point are arranged in a straight line on a common line, and the moving range of the first and second working points is defined by a straight line parallel to the horizontal axis of the lens barrel. Therefore, even if the diaphragm mechanism is attached to the zoom lens barrel at an angle, the corners of the housing do not protrude from the outer periphery of the zoom lens barrel, and the diaphragm mechanism 20 does not protrude from the zoom lens barrel. Can be installed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a zoom lens barrel according to the present invention.

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is an exploded perspective view of a stop mechanism of the zoom lens barrel according to the first embodiment of the present invention.

FIG. 4 is a view for explaining the operation of the aperture mechanism of the zoom lens barrel according to the first embodiment of the present invention;

FIG. 5 is a front view of a diaphragm mechanism of a zoom lens barrel according to a second embodiment of the present invention.

FIG. 6 is an exploded perspective view of a conventional aperture mechanism of a zoom lens barrel.

FIG. 7 is a front view of a conventional lens barrel aperture mechanism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... lens barrel (zoom lens barrel), 6 ... lens (front lens group), 7 ... lens (variator lens group), 8 ... lens (fixed master lens), 9 ... lens (moving master lens), 20, 30 ... throttle mechanism, 21,
31 ... housing, 21h, 31h ... corner, 22a, 3
2a: motor shaft, 23, 33: swing arm, 23
b, 33b... first operation point (first operation pin), 23c, 3
3c: second working point (second working pin), 24, 34: plate (lower plate), 24a, 34a: notch, 25,
35: plate (upper plate), 25a, 35a: notch.

Claims (2)

[Claims] 1. A two-plate plate having a cutout for light transmission is mounted on a housing so as to overlap with the housing, and the housing is mounted at a certain angle with respect to the longitudinal axis of the lens barrel. The first working point and the second working point are provided at both ends of a swing arm that swings around a motor shaft, and the first working point is provided at the first working point. An aperture mechanism for a lens barrel in which one plate is driven and the other plate is driven at a second operation point, wherein the second operation point is determined from a straight line connecting the first operation point and a motor shaft.
A diaphragm mechanism for a lens barrel, wherein an action point is offset toward a lens. 2. A two-plate with a cutout for light transmission is mounted on a housing so as to be superposed on the housing, and the housing is mounted at a certain angle with respect to the longitudinal axis of the lens barrel. A first mechanism and a second mechanism are provided at both ends of a swing arm that swings around a motor shaft, and the first mechanism is provided at the first mechanism. In a diaphragm mechanism of a lens barrel in which one plate is driven and the other plate is driven at a second operation point, the first operation point, the motor shaft, and the second operation point are arranged in a straight line on a common line, A diaphragm mechanism for a lens barrel, wherein a moving range of the first and second action points is symmetric with respect to a straight line parallel to a horizontal axis of the lens barrel.