JP3210395B2 - Iris device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a novel iris device . Specifically, the iris device moves in one direction 2
A drive mechanism having a plurality of aperture blades and for moving the aperture blades is located at an end of the outer casing in the one direction and near the aperture blades, and is a drive mechanism of the iris device. By devising the position, the width of one of the parts of the inner space of the outer casing that was located beside the iris device in the other direction above and was conventionally a dead space was expanded without increasing the width of the outer casing. It is an object of the present invention to provide a novel iris device that can effectively use this space.

[0002]

2. Description of the Related Art A lens barrel for a camera usually includes a required lens system including a movable lens such as a focusing lens for focusing and a zooming lens for adjusting an angle of view, and the movable lens described above. An actuator for moving the lens, an iris device for adjusting the amount of light, and the like are provided inside the outer casing. Usually, a focusing lens and a zooming lens are arranged on both front and rear sides of the iris device.

FIG. 7 shows an example a of a conventional camera lens barrel having such a structure.

In FIG. 1, reference numeral b denotes an outer case of a lens barrel a, which has a substantially rectangular cross section viewed from the front and rear, which is long in the vertical direction, and has a left and right width such as a zooming lens and a focusing lens. It has the minimum dimensions required to place the lens system. The optical axis of the lens system extends in the front-rear direction through substantially the center of the outer casing b in the left-right direction.

An iris device c is disposed substantially at the center in the front-rear direction inside the outer casing b. A relatively thin casing d having a vertically-long rectangular shape as viewed from the front-rear direction is provided. The two diaphragm blades e and f housed so as to be movable to each other, a motor g positioned to protrude rearward from the lower end of the casing d, and a central portion fixed to a rotation shaft h of the motor g. A drive arm i, and both ends of the drive arm i are rotatably connected to two diaphragm blades e and f. When the drive arm i rotates, the diaphragm blades e and f are connected to each other. They are moved in directions opposite to each other, whereby the effective apertures of the light passage holes j, j (only one is shown) formed in the front and rear walls of the casing d are adjusted.

[0006]

However, in the above-mentioned camera lens barrel a, the left and right widths of the iris device c are somewhat smaller than the left and right widths of the space in the outer casing b. Spaces k and k are formed on both sides, however, since the left and right widths of these spaces k and k are too small for arranging some members here, it is difficult to use them effectively. It was dead space.

In addition, since the iris device c is disposed substantially at the center of the inside of the outer casing b in the front-rear direction, the space inside the outer casing b is divided into front and rear by the iris device c. As a result, it is necessary to separately provide a focusing axis and a guide axis for guiding the zooming lens having a common optical axis, which may cause a reduction in optical accuracy or a mechanical error. This causes various problems such as a decrease in strength and an increase in the number of parts.

[0008]

In order to solve the above-mentioned problems, the iris device according to the present invention comprises first and second aperture blades that move on a plane perpendicular to the optical axis to adjust the amount of light, In an iris device including a motor that drives the diaphragm blade, a rotating arm that transmits rotation of the motor to the diaphragm blade, and a casing that houses the diaphragm blade and the rotating arm, the first diaphragm blade includes: Two guided slits are respectively formed near both ends of the one side portion, and the outer shape of the casing along the two guided slits is different from the optical axis in the moving direction of the diaphragm blade. to to
The casing is partially recessed and the two guided slits are also different in distance from the optical axis, and the second diaphragm blade is formed with two guided slits near both ends on one side thereof. At the same time, an engaging long hole is formed at a position where the deviation from the optical axis with respect to the moving direction of the diaphragm blade can be increased, and the center of the engaging long hole is located outside the two guided slits, The outer shape is such that the distance from the optical axis to the direction of movement of the first and second aperture blades is larger on the other side opposite to the one side than on the one side, and the motor is provided with the first and second motors. It is spaced apart from the plane including the optical axis parallel to the moving direction of the diaphragm blades of the parts of the casing
The lens moves in the front-rear direction outside the part
A guide shaft for guiding the movement is provided.

[0009]

Therefore, in the iris device of the present invention, the first
Of the aperture blade of the lens has a partially different distance from the optical axis
And close to both ends of one side of the aperture blade
The two guided slits formed separately are also separated from the optical axis by a distance.
Separation was made different, and formed on the second diaphragm blade
The center of the long engagement hole is formed on each of the second diaphragm blades.
So that it comes outside the two guided slits,
Partially reduce the outer shape of the casing that houses the aperture blades
It becomes possible. Therefore, the lens is
The guide shaft that guides the
Nothing by placing it outside of the dents
Increase the movement span of the lens support frame without disturbing
Can be In this way, the conventional dead space
If you can use the part that was
This makes it possible to further reduce the size of the device.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the iris device of the present invention will be described below with reference to the embodiments shown in the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a lens barrel.

Reference numeral 2 denotes an outer casing of the lens barrel 1, which has a substantially rectangular parallelepiped outer shape. That is, the outer casing 2 has a rectangular shape that is long in the up-down direction when viewed from the front-rear direction, and from the left-right direction (a leftward direction is a leftward direction in FIG. 1 and a rightward direction is a rightward direction in FIG. 1). It has a rectangular shape that is long in the front-back direction when viewed, and its height is approximately 1.5 times the left-right width. The shape of the internal space 3 of the outer casing 2 as viewed from the front-back direction is a vertically long rectangle similar to the outer shape viewed from the same direction.

The outer casing 2 has a box-shaped outer casing 4 having substantially the same size as the outer casing front 4 having a rectangular tube-shaped outer casing front part 4 having both front and rear open ends and an open front face. The rear portion 5 is formed by integrally connecting a lens support frame 6 and the like, which are arranged inside the front end portion of the outer housing front portion 4 so as to fit inside.

7 is a first group lens, 8 is a second group lens, 9
Denotes a third lens group, and 10 denotes a fourth lens group.
The three lens groups 7, 8, 9, and 10 share one optical axis 11 extending in the front-rear direction through a position slightly higher than the central portion of the outer casing 2 as viewed in the front-rear direction, and The first group lens 7 is held by the lens support frame 6 to close the front end face of the outer casing 2, and the third group lens 9 is held by another lens support frame 12. The lens support frame 12 is fixed to an iris device 13 arranged at a substantially central portion in the front-rear direction in the outer housing 2.

The second group lens 8 is a zooming lens, the fourth group lens 10 is a focusing lens, and these two movable lenses 8 and 10 are movable on the front and rear sides of the iris device 13 in the front-rear direction. The two lens holders 14 and 15 provided are separately held.

The front lens holder 14 has a main portion 16 having a substantially square shape when viewed from the front and rear, and two arms 17 and 17 ' projecting from the lower left and upper right corners of the main portion 16, respectively. A lens holding hole 16a is formed in the center of the main part 16, a nut 18 is fixed to the upper arm 17, and a U-shaped cover opened at the lower end to the lower arm 17 '. A guide notch 19 is formed. The zooming lens 8 is supported by the lens holding hole 16a.

The rear lens holder 15 is formed integrally with a main portion 20 having a substantially square shape when viewed from the front and rear, and two arms 21 and 21 'protruding from lower left and upper left positions of the main portion 20. A lens holding hole 20a is formed in the center of the main part 20, and the focusing lens 10 is supported in the lens holding hole 20a.

A coil portion 22a of a moving coil type actuator 22 is fixed to the upper arm 21.
The lower arm 21 'is formed with a U-shaped guided notch 23 opened at the lower end thereof.

Reference numeral 24 denotes a stepping motor arranged at the upper right position in the space of the outer casing rear portion 5, extending to the inside of the outer casing front portion 4 of the rotating shaft 25 and in parallel with the optical axis 11. The portion of the rotating shaft 25 located inside the outer casing front part 4 is a ball screw 25a.

Reference numeral 26 denotes a guide shaft arranged so as to extend from the front end to the rear end of the lower left portion of the internal space 3 of the outer casing 2 and extend in parallel with the optical axis 11.

In the lens holder 14 for the zooming lens 8, the ball screw 25 a is screwed into a nut 18, and the guided notch 19 is slidably engaged with a guide shaft 26. Holder 14
Is disposed in the front half of the outer casing 2 so as to be movable along the optical axis 11. When the stepping motor 24 is driven, the ball screw 25a is rotated, whereby the nut 18 is fed, so that the lens holder 14 moves along the optical axis 11.

A guide shaft 22 of a moving coil type actuator 22 is located at a position closer to the left of an upper end portion in the outer casing rear portion 5.
b is arranged so as to extend in parallel with the optical axis 11, and the coil portion 22 a supported by the focusing lens holder 15 is slidably supported by the guide shaft 22 b, and is guided by the lens holder 15. The notch 23 is slidably engaged with the guide shaft 26, whereby the lens holder 15 is disposed in the rear half of the outer casing 2 so as to be movable along the optical axis 11, and the actuator 22 is driven. Then, the coil portion 22a is urged to move, and the lens holder 15 is moved along the optical axis 11.

Reference numeral 27 denotes an image sensor holder, on the front of which an image sensor 28 is supported. The image sensor holder 27 is fixed to the rear wall 29 in a state where the hole 29a formed in the rear wall 29 of the outer casing rear portion 5 is inserted, whereby the image sensor 28 is disposed behind the focusing lens 10. You.

Thus, the outer casing 2 is passed through the first wall lens 7.
The light incident on the inside is a zooming lens 8 and a third group lens 9.
The light is transmitted through the focusing lens 10 so as to focus on the light receiving surface of the image sensor 28.

Reference numeral 30 denotes a low-pass filter made of a crystalline lens, which is disposed between the focusing lens 10 and the image pickup device 28.

The iris device 13 includes a thin casing, two diaphragm blades movably housed in the casing in a vertical direction, and a drive mechanism for moving the diaphragm blades.

Reference numeral 31 denotes a casing, and the casing 31
Is a flat plate-shaped main part 32 having an open front surface and the main part 3
2 and a cover plate 33 for closing the front surface.

The main part 32 includes a rear wall 34 in the shape of a rectangular flat plate that is long in the vertical direction, a peripheral wall 35 having a small front-rear width protruding forward so as to extend along the peripheral edge of the rear wall 34, and a rear wall 34. Small support pins 36, 36 and 36 'projecting forward two by two from the left and right side edges of the front face, respectively.
36 'and a frame portion 37 having a small front-rear width protruding rearward from a peripheral portion of an opening 34a formed in a little more than a quarter on the lower end side of the rear wall 24 are integrally formed of synthetic resin. A circular light passage hole 34b is formed at the center between the upper end of the wall 34 and the opening 34a.

The cover plate 33 has a flat plate shape having the same shape as that of the main portion 32 as viewed from the front-back direction. The cover plate 33 is attached to the main portion 32 so as to close the front surface thereof. A shaped casing 31 is formed.

Reference numeral 33a denotes a light passage hole formed in the cover plate 33 at a position facing the light passage hole 34b of the main portion 32.

The overall height of the casing 31 is the outer casing 2
The height of the inner space 3 is the same as the height of the space 3
Of which it is three weak quarters of the width, also, the casing 3
Except for the left and right ends of the upper end face 1, the portion is formed in an arc shape bulging upward .

The portion slightly lower than a quarter from the bottom of the casing 31 is ubiquitous slightly to the right with respect to the remaining portion.

The opening 34a formed at the lower end of the rear wall 34 has a substantially oval shape extending in the left-right direction.

Reference numerals 38 and 39 denote diaphragm blades, which are formed of a rigid resin film.

One of the diaphragm blades 38 has a substantially semicircular large notch 38a opened at the upper edge thereof, and two guided members formed to extend vertically in positions respectively approaching the upper and lower ends on the left side thereof. It has slits 38b, 38b and a long engagement hole 38c formed in the lower end thereof in the left-right direction, and the two left support pins 36, 36 of the casing 31 in the guided slits 38b, 38b slide. By being freely engaged, the casing 31 is movably supported in the vertical direction.

The other diaphragm blade 39 has a substantially inverted J-shape.
a are formed, and slits 39b, 3b are formed so as to respectively extend in the vertical direction near the upper and lower ends on the right side.
9b and an elongated slot 39c formed in the lower end thereof and extending in the left-right direction. The slits 39b, 39b are positioned so as to overlap one of the aperture blades 38 from the rear side.
, Two right supporting pins 36 ′ of the casing 31,
36 'is slidably engaged with the casing 3
1 is movably supported in the vertical direction.

Reference numeral 40 denotes a drive mechanism of the iris device 13, which comprises a motor and a rotating arm driven by the motor.

A motor 41 has a front end 41b of an outer shell 41a fixed to the frame 37 formed on the rear wall 34 of the casing 31 so as to close the rear surface from the rear side. The front end of the rotating shaft 41c of the 41 is located at the center of the opening 34a of the rear wall 34.

Reference numeral 42 denotes a rotating arm, the center of which is fixed to the rotating shaft 41c of the motor 41. Small engaging pins 42 are provided at both ends of the rotating arm 42.
a, 42a project forward, and these engaging pins 4
2a and 42a are separately and slidably engaged with engagement long holes 38c and 39c formed in the two diaphragm blades 38 and 39, respectively.

Accordingly, when the rotating arm 42 is rotated, the two engaging pins 42a, 42a are displaced in directions opposite to each other up and down.
Are moved in opposite directions.

As shown in FIG. 3, when one of the diaphragm blades 38 is at the upper end of the moving range (the other diaphragm blade 39 is at the lower end of the moving range), these diaphragm blades are at the lower end. 38, 39 are positioned so as to completely close the notches 38a, 39a of each other, whereby the light passage holes 33a, 34b of the casing 31 are fully closed, and as shown in FIG. Aperture blade 3
In a state in which the diaphragm blade 8 is at the lower end in the moving range (the other diaphragm blade 39 is in the upper end in the moving range), the notches 38a, 39a of the diaphragm blades 38, 39 complement each other to form a substantially circular shape. The light passing holes 33a and 34b of the casing 31 are fully opened. Therefore, by controlling the positions of the aperture blades 38, 39, the apertures of the light passing holes 33a, 34b are adjusted, whereby the amount of light passing through the iris device 13 is adjusted.

The lens support frame 12 holding the third lens group 9 is fixed to the rear surface of the rear wall 34 of the casing 31.

The iris device 13 is disposed substantially at the center in the front-rear direction inside the outer casing 2, and its light passage holes 33 a, 34 b are located on the optical axis 11 of the lens systems 7, 8, 9, 10 in the left-right direction. It is arranged so that it may be located.

When the iris device 13 is arranged in this manner, the portion of the casing 31 that is slightly more than a quarter at the lower end side, that is, the right side of the portion deviated rightward from the remaining portion, is outside. The drive mechanism 40 is positioned so as to be in contact with the right side wall 43 of the housing 2 and is biased toward the right side wall 43.

Accordingly, a space 3a having a relatively large left-right width is formed in the lower part on the left side of the iris device 13 in the inner space 3 of the outer casing 2, and the left-right width is slightly more than a quarter of the lower end side of the casing 31. It is approximately twice the left and right width of the space formed on the left and right sides of the part excluding the part.

Since the space 3a has a relatively large left and right width, it is possible to arrange some members in the space 3a. In this embodiment, the space 3a is used to Holder 14
And a guide shaft 26 for supporting the same.

[0047]

As is apparent from the above description, the iris device according to the present invention comprises first and second aperture blades for adjusting the amount of light by moving on a plane perpendicular to the optical axis, and the aperture blades. An iris device comprising: a motor that drives the diaphragm blade; a rotating arm that transmits rotation of the motor to the diaphragm blade; and a casing that houses the diaphragm blade and the rotating arm.
In the diaphragm blade, two guided slits are separately formed near both ends of one side thereof, and the outer shape of the casing along the two guided slits is different from the optical axis with respect to the moving direction of the diaphragm blade. The distance of the casing is different
And the two guided slits also have different distances from the optical axis, and the second diaphragm blade has two guided slits formed near both ends on one side thereof, respectively. An engagement slot is formed at a position where the deviation from the optical axis with respect to the direction of movement of the diaphragm blade can be increased, and the center of the engagement slot is located outside the two guided slits. The outer shape of the motor increases the distance from the optical axis with respect to the direction of movement of the first and second diaphragm blades on the other side opposite to the one side, and the motor operates on the first and second sides. It is located away from the plane containing the optical axis parallel to the direction of movement of the diaphragm blades, and is partially recessed in the casing.
Guide the lens to move out of the
And a guide shaft to be driven .

Therefore, in the iris device of the present invention,
The outer diameter of the first diaphragm blade is partially different from the optical axis.
And close both ends of one side of the aperture blade.
In addition, the two guided slits formed separately from the optical axis
And the second diaphragm blade
The center of each of the engaged long holes is separately formed in the second diaphragm blade.
So that it's outside the two guided slits
The outer shape of the casing that houses the diaphragm blades etc. is partially
It becomes possible to indent. Therefore, the lens
A guide shaft that guides the
By placing it outside of the partially dented part,
Extends the movement span of the lens support frame without disturbing anything
Can be done. In this way, the conventional dead space
Can be used effectively
If this is the case, the size of the device can be further reduced.

It should be noted that the structures, shapes, and the like of the respective parts shown in the above-described embodiments are merely examples of the embodiment for carrying out the present invention, and these limit the technical scope of the present invention. Must not be interpreted.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of an iris device of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged sectional view taken along line III-III in FIG. 2;

FIG. 4 is a sectional view of a main part along a line IV-IV in FIG. 3;

5 is an exploded perspective view showing an iris device included in the lens barrel shown in FIG. 1 in an exploded manner.

FIG. 6 is an enlarged front view showing a fully opened state of an iris device included in the lens barrel shown in FIG. 1;

FIG. 7 is a sectional view of a main part showing an example of a conventional camera lens barrel.

[Description of Signs] 8 Lens 10 Lens 11 Optical axis 13 Iris device 26 Guy that guides the lens to move in the front-back direction
Guide shaft 31 Casing 38 First diaphragm blade 38b Guided slit 39 Second diaphragm blade 39b Guided slit 39c Long engaging hole 41 Motor 42 Rotating arm

Claims (1)

(57) [Claims] 1. A first and a second diaphragm blade for adjusting the amount of light by moving on a plane perpendicular to the optical axis, a motor for driving the diaphragm blade, and a rotation transmitting the rotation of the motor to the diaphragm blade. An iris device comprising a moving arm, a casing accommodating a diaphragm blade and a rotating arm, wherein the first diaphragm blade has two guided slits formed near both ends on one side thereof, respectively. , Quai distance from the optical axis with respect to the moving direction of the outer shape aperture blades of the casing along the two guided slits in the different
In addition, two guided slits are formed so that the distance from the optical axis is different from that of the two guided slits, and two guided slits are respectively formed near both ends of one side of the second diaphragm blade. At the same time, an engaging slot is formed at a position where the deviation from the optical axis with respect to the moving direction of the diaphragm blade can be increased, and the center of the engaging slot is located outside the two guided slits, The casing has an outer shape whose distance from the optical axis in the moving direction of the first and second diaphragm blades is larger on the other side opposite to the one side, and the motor is: is spaced apart from the plane including parallel the optical axis with respect to the direction of movement of the first and second diaphragm blades, the lens on the outside of the partially recessed portion of the casing
A guide shaft that guides the
Iris and wherein the a.