JPH06201967A - Lens barrel - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a lens barrel having a large degree of freedom in optical design and mechanical design, a low possibility of foreign matter mixing during the assembly process, and a component detection device that facilitates component replacement. thing. [Structure] Fixed lens barrel 2 fixed to the camera body
A movable lens barrel 3 movably supported with respect to the fixed lens barrel, a driving force transmission device provided on the fixed lens barrel or the movable lens barrel, the driving force transmission device and the lens barrel 3 And a signal reading device 13 arranged on the other side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel having a signal detecting device for electrically detecting the position of a moving lens group.

[0002]

2. Description of the Related Art In a conventional lens barrel of this type,
The position information of the movable lens group detected by the signal detection device is input to an information processing device such as a microcomputer and is used to appropriately perform various controls.

FIG. 6 shows a vertical sectional view of a conventional lens barrel. In FIG. 6, 201 is a mount having a claw portion 201a for connecting to the camera body, 202 is a fixed cylinder connected to the mount 201, and has a guide groove 202a parallel to the optical axis. 203 is a fixed cylinder 202
The zoom ring 203 is rotatably supported with respect to the outer cylinder portion 20 for performing a zooming operation.
3a and an inner cylinder portion 203b having a cam groove 203c.

Reference numeral 204 denotes a male helicoid ring, which is formed with a cam groove 204a with which a roller 205 mounted on the zoom ring 203 is engaged, and a helicoid 204b on the outer peripheral portion.
However, the inner peripheral portion is provided with a guide groove 204c with which the straight advance key 206 attached to the fixed cylinder 202 is engaged.

Reference numeral 207 is a front lens barrel holding a lens unit L201, and the male helicoid ring 20 is provided on the inner peripheral portion thereof.
Helicoid 20 screwed with 4 helicoid 204b
7a is provided.

Reference numeral 208 denotes a rear lens barrel which holds the lens group L202, and rollers 209 which are fitted into the guide groove 202a of the fixed cylinder 202 and the cam groove 203c of the zoom ring 203 are attached to the outer peripheral portion of the lens barrel L202. ing. Reference numeral 210 denotes a contact member that is attached to the mount 201 and serves as an electrical contact with the camera body, and is connected by soldering to an annular disc-shaped circuit board 211 on which electric parts are mounted to form an electric circuit. ing.

Reference numeral 212 denotes a flexible printed board having one end connected to the circuit board 211 by soldering and the other end being attached to the fixed cylinder 202. A part of the flexible printed board has a gray code pattern for signal generation. is doing. A brush 213, which is in sliding contact with the gray code pattern of the flexible printed board 212, is attached to the outer cylinder portion 203a of the zoom ring 203 at a position where the inner cylinder portion 203b of the zoom ring is cut out. A rubber ring 214 is wound around the outer periphery of the zoom ring 203 to improve the operability in zooming operation.

The operation of the lens barrel having the above structure will be described below.

(Variable magnification operation) When the zoom ring 203 is rotated around the optical axis, the rear group lens barrel 208 is supported by the guide groove 202a of the fixed barrel 202 so that the roller group 209 can move only in the optical axis direction. Therefore, the cam groove 20 of the zoom ring 203
3c is moved along the optical axis along the locus. At the same time, the male helicoid ring 204 is supported by the guide groove 204c and the linear key 206 fixed to the fixed barrel 202 so as to be movable only in the optical axis direction. Can be moved in the direction.

At this time, since the relative movement does not occur between the male helicoid ring 204 and the front lens barrel 207, the lens unit L201 moves along the trajectory opposite to the cam groove 204a like the male helicoid ring 204. To be made.

As described above, the zooming operation is performed by rotating the zoom ring 203 around the optical axis and moving the lens groups L201 and L202 in the optical axis direction.

(Focusing Operation) By applying a force in the direction of rotation to the front lens barrel 207, the helicoid 204b and the helicoid 207a are screwed together to rotate the front lens barrel 207 having the lens group L201 while rotating the optical axis. This can be done by moving in the direction.

In the conventional lens barrel described above, the brush 2 is used.
13 and the flexible printed board 212 and a part of the circuit on the circuit board 211, the moving lens group L
The position detecting devices 201 and L202 are configured. That is, as the zoom ring 203 rotates, the brush 213
Moves while slidingly contacting the gray code pattern on the flexible printed board 212, the instantaneous position of the brush 213 is electrically detected by the detection circuit on the circuit board 211, whereby the position of the zoom ring 203, that is, the lens system. The focal length can be detected.

[0014]

However, in the above-mentioned conventional example, since the flexible printed board 212 having the gray code pattern for position detection is attached to the fixed cylinder 202, the guide groove 2 formed in the fixed cylinder 202.
02a and the flexible printed board 212 cannot be overlapped in the same place. Because, in the overlapping place, the flexible printed board 2 is pressed by the contact piece pressure of the brush 213.
This is because 12 is stressed and the wire breaks.

Therefore, the length of the guide groove 202a is limited, and it becomes impossible to secure a sufficient amount of movement of the moving lens unit L202, so that the target optical performance is not satisfied. Alternatively, if the guide groove 202a is extended to the front of the lens barrel in order to secure a sufficient amount of movement of the moving lens unit L202, there is a problem that the total length of the lens barrel becomes longer than necessary.

In order to solve these problems, the guide groove 20
If it is attempted to shift the phase in the rotation direction between the flexible printed board 212 and the flexible printed board 212, since three guide grooves 202a are normally required for accuracy, the range in which a signal of the flexible printed board can be generated is extremely narrowed, and zooming is performed. The rotation angle of the operation must be extremely small and the zoom ring 2
03, the cam groove 203c has a steep gradient,
Another problem arises in that the movement becomes unsmooth and the operational feeling deteriorates.

Therefore, adverse effects such as the amount of movement of the moving lens group on the optical design are large, which may lead to deterioration of optical performance, or may lead to an increase in the size of the lens barrel and a deterioration in operational feeling. Further, there is no degree of freedom in the shape of the fixed barrel itself in order to form the position detecting device, which is also a great constraint in the design of the lens barrel.

Furthermore, since the work of attaching the flexible printed board 21 to the fixed cylinder 202 must be performed at the earliest stage of the assembly work, the flexible printed board 212 is frequently broken, and the brush sliding surface is used in the subsequent process. Flexible printed board 212 due to foreign matter mixed in
When the replacement of the flexible printed board 212 is required, almost all of the assembly must be disassembled, so that the efficiency of the replacement work of the flexible printed board 212 is very poor.

An object of the present invention is to provide a lens barrel that solves the above problems.

[0020]

According to the present invention, a fixed lens barrel fixed to a camera body, a movable lens barrel movably supported with respect to the fixed lens barrel, and the fixed lens barrel. Or a driving force transmission device provided in the movable lens barrel, a signal generation device provided in one of the driving force transmission device and the lens barrel, and a signal reading device provided in the other. As a result, it is possible to provide a lens barrel equipped with a signal detection device that has a high degree of freedom in optical design and mechanical design, has a low possibility of foreign matter during the assembly process, and allows easy replacement of a flexible printed board. is there.

[0021]

【Example】

First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view of a lens barrel best showing the features of the present invention. The same parts as those of the conventional apparatus shown in FIG.

A flexible terminal 212 has one end connected to the circuit board 211 by soldering and is attached to the drive force transmission device C and the other end attached to a holding base 215 integrally provided in the drive force transmission device C. It is a printed board, and a gray code pattern as a signal generator is provided on the portion attached to the holding table 215. here,
The surface of the holding base 215 to which the flexible printed board is attached is configured to be on the outer diameter side of the inner cylinder portion 203b of the zoom ring 203.

On the other hand, a brush 213 as a signal reading device which is in sliding contact with the gray code pattern of the flexible printed board 212 is attached to the outer peripheral portion 203a of the zoom ring 203. Further, the driving force transmission device C is provided with an output gear 216, and the output gear 216 is meshed with the gear portion of the front lens barrel 207, and the rotation thereof causes the focusing operation.

In this embodiment, a flexible printed board 212 having a signal generating gray code pattern is attached to a holding base 215, and the flexible printed board attachment surface of the holding base 215 is attached to the inner cylinder portion 203 of the zoom ring 203.
By being configured to be on the outer diameter side with respect to b, it is possible to extend the length of the guide groove 202a to the mount side, and the required lens group L without affecting the overall length of the lens barrel.
A sufficient amount of movement of 202 can be secured, which contributes to improvement of optical performance.

Further, since the brush 213 and the flexible printed board 212 come into contact with each other, the inner cylinder portion 2 of the zoom ring 203 is
Since it is not necessary to provide a hole in 03b and the rotation direction angle of the flexible printed board is not influenced by the guide groove 202a, it is easy to increase the rotation angle of the zoom ring, and there is a margin in the gradient of the cam groove 203c. it can. Therefore, it is advantageous for the smoothness of movement and the setting of the operation torque, which leads to the improvement of the operation feeling.

Further, the work of incorporating the flexible printed board 212 and the holding base 215 can be performed near the final stage of the assembling work regardless of the assembly of the optical movement system, and the brush in the subsequent process can be used. The possibility of foreign matter entering the sliding surface is extremely low, and even when the flexible printed board 212 is replaced due to a break or the like, it can be replaced by disassembling only a small part, and the replacement work efficiency is very good.

Second Embodiment FIG. 2 is a sectional view of a lens barrel showing a second embodiment of the present invention. In the figure, reference numeral 21 is a fixed barrel.
A bayonet mount 22 that is coupled to a camera (not shown) is attached to one end of 1. Stationary ring is secured is fitted to the fixed barrel 21 23, 24 focusing lens L ₄ ~L ₆
Is a first moving ring that holds the focusing lens L ₇ , and a second moving ring that holds the focusing lens L ₇ is fixed to the first moving ring 24 by screwing or the like. 26 is a mount 22
Rear interior ring fixed to the lens, 27 is a focusing lens L _{1 to} L
This is a third mobile ring that holds ₃ , and this third mobile ring 2
The inner peripheral surface of 7 has a fitting portion 27a that fits with the outer diameter portion 24a of the first moving ring 24, and the first moving ring 24 and the third moving ring 27 are integrated by screws 28. ing.

Reference numeral 29 is a rotary ring fitted to the fixed cylinder 21,
Reference numeral 30 denotes a roller fixed to the rotating ring 29 with a screw 31, and the roller 30 is rotated in a fixed position with respect to the fixed cylinder 21 by fitting the roller 30 into the circumferential groove 21a provided in the fixed cylinder 21. Is configured to. On the other hand, reference numeral 32 is a roller fixed to the first moving ring 24 with a screw 33, and this roller 32 is a lead cam groove 29 provided on the rotating ring 29.
It is fitted to a.

Reference numeral 34 denotes a straight-moving key screwed with a fixed cylinder 31 and a screw 35, and a key groove 24b of the first moving ring 24.
Is fitted to. That is, when the rotary ring 29 is rotated by the output of the ultrasonic motor A for focusing through the driving force transmission device C and the gears 79 and 9b, the first moving ring 24 moves the roller 32.
Then, the lead cam 29a moves straight.
Due to this rectilinear movement, the first moving ring 24, the second moving ring 25, and the third moving ring 27 are integrated as described above, so that the lenses L _{1 to} L ₇ all move straight to focus. It can be performed.

Reference numeral 36 denotes a manual ring. The output from the gear 36a due to the rotation of the manual ring 36 is received by the gear 86 and transmitted to the gear 79 and the gear 9b through the gear train in the driving force transmission device C. That is, the rotating ring 29 is rotatable even when the manual ring 36 rotates. Reference numeral 37 denotes a name ring screwed to the fixed cylinder 21 with a screw 38, and the lens product name and the like are printed on the outer peripheral surface thereof. Reference numeral 39 is a decorative ring screwed and fixed to the filter screw 27a provided on the third moving ring 27.

D is a diaphragm blade unit positioned on the first moving ring 24, EMD is a motor for driving the diaphragm blade unit D, and the motor EMD and the diaphragm blade unit D constitute an electric diaphragm device. The electric diaphragm device is sandwiched and held between the first moving ring 24 and the third moving ring 27.

Reference numeral 40 is a vibration-proof sheet for preventing dust and dirt from entering the lens barrel, and 41 is attached to the mount 22.
It is a contact member that serves as an electrical contact with the camera body, and is connected by soldering to a circuit board 42 forming an electric circuit on which electric parts are mounted via a flexible printed board 43. 44 is a flexible printed board,
One end thereof is connected to a connector 45 provided on the circuit board 42, and the other end is a signal ground plate 85 in the driving force transmission device C.
And has a pattern as a signal generator in a part thereof.

A brush 46 as a signal reading device is configured to be in sliding contact with this signal generating pattern. The brush 46 is fixed to the brush holding plate 47 by spot welding or the like, and the brush holding body 47 is fixed to the rotating ring 29 by screws 48, so that the rotating ring 29
The rotation allows the brush 46 to slide on the signal generating pattern provided on the flexible printed board 44 to detect the lens position. The brush 46, the brush holding plate 47, and the screw 48 are provided in the cutout portion 2 of the fixed cylinder 21.
It is located in 1b.

FIG. 3 is an exploded view of the essential part showing the driving force transmission device C,
FIG. 4 is a cross-sectional view of the main part thereof, and in FIGS.
1 is a cylindrical vibration elastic body made of a metal material, 52 is a pressing body made of a metal material having an outer diameter that is the same as the outer diameter of the vibration elastic body 51, and 53a to 53e are the outer diameter of the vibration elastic body 51. A ring-shaped piezoelectric element plate having the same outer diameter, 54
Reference numerals a to 54d are electrode plates of the piezoelectric element plates 53a to 53e.

Then, the vibrating elastic body 51 and the pressing plate 52 are
Between the electrode plates 54a to 54f and the piezoelectric element plates 53a to 5
By alternately arranging 3e, the bolt 55 is passed through the pressing body 52 and screwed to the vibrating elastic plate 51, these are integrally fixed, and the stator (vibrator) of the ultrasonic motor A is configured.

The ultrasonic motor A has a stator electrode plate 5
By applying alternating voltages having different phases from a power supply circuit (not shown) to the piezoelectric element 4, the piezoelectric element plate 53 forms mechanical vibrations in the stator, and by combining these vibrations, the rotor 56 that frictionally contacts the front end portion of the stator 56 Friction drive. The rotor 56 has a rear end portion (friction, contact portion) 56a brought into contact with the drive surface 51a of the vibrating elastic body 51, and an appropriate friction force is obtained by pressurization by a pressure spring 60 described later.

Reference numeral 57 is a rotor coupling member fixed to the rotor 56, and is provided with a recess 57a so that the rotation output member 58 can be integrally rotated. 58 is a gear part 58
a rotor output member having a projection 58b that engages with the recess 57a of the rotor coupling member 57, or the rotor 5
While the rotation of 6 is transmitted to the outside, it is slidable in the thrust direction with respect to the rotor 56. Reference numeral 59 is a bearing provided on the inner diameter portion of the rotation output 58.

Reference numeral 60 denotes a pressure spring, which is the rotor coupling member 5
By pressing 7, the rear end portion 56a of the rotor 56 presses the drive surface 51a of the vibrating elastic body 51, and the pressing force generates a frictional force between the vibrating elastic body 51 and the rotor 56. Has been done. Reference numeral 61 is a holding member that fits the inner circumference of the bearing 59 on the outer circumference, and is inserted into the tip portion 55a of the bolt 55 and tightened with a nut 62 to form the ultrasonic motor A.

The pressing force of the pressure spring 60 is generated through the bearing 59 and the rotation output member 58 by incorporating the holding member 61 into the tip portion 55a of the bolt 55.

In this ultrasonic motor A, the holding member 61 is sandwiched by an anti-vibration rubber (for preventing the vibration of the ultrasonic motor itself) 63 and a motor mount 64.
It is fixed by screwing with a screw 65.
The motor mount 64 is fixed to the first metal base plate 66 by adhesion, screwing or the like.

67 is a second metal base plate, 68 is a connecting gear which is rotatably fitted to the shaft 68a and meshes with the gear portion 58a of the rotation output member 58 of the ultrasonic motor A.
Is transmitted to the gear 69. Reference numeral 70 denotes a first outer member fixed to the gear 69, and 72 denotes a second outer member, which has a tapered surface 70a in contact with the ball member 71 on the inner circumference, and the second outer member 72 has an inner circumference. Taper surface 7
The ball member 71 is radially pressed and sandwiched between the 2a and the tapered surface 70a of the first outer member 70 and the inner member 74 fixed to the gear 73.

Reference numeral 75 is a pressure member that generates a frictional force between the ball member 71 and the first outer member 70 and the second outer member 72. This pressure member 75 is the second outer member. Pressure is also applied in the axial direction so that 72 and the gear 69 rotate integrally. Reference numeral 76 is a cap screwed and fixed to the threaded portion 69a of the gear 69 so as to generate a pressing force by the pressing member 75.

The ball member 71 is radially nipped by the inner member 74 fixed to the gear 73, the first outer member 70 and the second outer member 72, and frictional force is exerted around the inner member 74. The retainer gear 77 is driven to rotate by being rotated by, and at least three or more are arranged concentrically. The retainer gear 77 holds the ball member 71 so as to transmit the rotation of the ball member 71 about the rotation axis of the gear 73. Reference numeral 78 denotes a tightening washer that fixes the components denoted by reference numerals 69 to 77 in the axial direction to unitize them, and the driving force transmission mechanism unit B is configured in this manner.

Numeral 79 is an output gear which is rotatably fitted to the shaft 79a and meshes with the gear portion 29b of the rotary ring 29 to transmit the rotation to the rotary ring 29. Numerals 80 to 82 rotate the pulse plate 83. Gear to be transmitted, 84 is a signal main plate 85
The signal from the pulse plate 83 is transmitted to a lens drive control circuit (not shown) via a part of the flexible printed board 44. The signal base plate 85 is fixed to the second metal base plate 67 by adhesion, screwing or the like, and the signal generating pattern portion of the flexible printed board 44 is attached.

Reference numeral 86 is a manual input gear that is fitted in the hole of the signal ground plane 85 and transmits the rotation of the manual ring 36 to the gear 73 by meshing with the gear portion 36a. Reference numeral 87 is a friction spring, and the friction spring 87 is configured to apply a frictional force to the rotation of the manual input gear 86 itself by stopping with a screw 88 and pressing the manual gear 86.

Numerals 89 and 90 are screws for fixing the first metal base plate 66 and the second metal base plate 67 to complete the unit of the driving force transmission device C. Reference numeral 91 denotes an electrode plate 54 driven by a control circuit (not shown) for driving the ultrasonic motor A.
It is a flexible printed board for applying an alternating voltage to.

The operation of the second embodiment having the above structure will be described below.

(Automatic focusing) When a lens drive signal is received from the drive circuit on the basis of a sensor output (not shown) provided in a camera (not shown), the electrode plates 54a, 5 of the ultrasonic motor A are received.
AC voltage is applied to 4b, 54d, and 54f, and the rotor 5
6 rotates in a predetermined direction. The rotation direction of the rotor 56 is determined by reversing the phase advances of, for example, two alternating voltages having different phases. This rotor 5
The rotation output member 5 is integrated with the rotor 56 by the rotation of 6
8 also rotates, and the gear 6 is passed through the connecting gear 68.
The rotational force is transmitted to 9, and the first and second outer members 70, 72 integrally assembled with the rotational force also rotate. At this time, a frictional force acts between the first and second outer members 70 and 72 and the ball member 71 due to the pressure applied by the pressure member 75.

Here, the gear 73 is the inner member 7 in which the frictional force (by the friction spring 87) acting on the connected manual input gear 86 is fixed to the gear 73.
Since the holding force is larger than the frictional force between the ball 4 and the ball member 71, it does not rotate during automatic focusing.

Therefore, the rotation of the gear 69 and the first and second outer members 70 and 72 causes the ball member 71 to rotate around the inner member 74 while rolling around the shaft portion of the gear 73, and thereby the retainer gear. 77 is driven to rotate, the rotation is transmitted to the gear 79, and the rotating ring 29 which is interlocked with the gear 77 rotates at a fixed position.

By this rotation, the first moving ring 24 is guided by the straight advance key 34, and the roller 33 and the lead cam 29b.
As a result, the second moving ring 25 and the third moving ring 27, which are integrally formed with the first moving ring 24, move at the same time. Therefore, the lenses L _{11 to} L ₇ are all moved straight, and the automatic focusing operation is performed.

(Manual Focusing Operation) When a rotational force is manually applied to the manual ring 36 from the outside, the output from the gear portion 36a of the manual ring 36 is transmitted to the gear 73 via the manual input gear 86. At this time, the gear 7
A frictional force is exerted between the inner member 74 and the ball member 71 fixed to the No. 3 by the pressure of the pressure member 75.

Contrary to the case of automatic focusing, the frictional force between the rotor 56 and the stator 51 of the ultrasonic motor A is now changed to the first and second outer members 70 and 72 and the ball member. The gear 69 does not rotate because it is larger than the frictional force with 71. Therefore, the rotation of the gear 73 causes the ball member 71 to rotate around the inner member 74 while rolling around the shaft portion of the gear 73, and the retainer gear 77 is driven to rotate to rotate the gear 79 → rotation as in the case of automatic focusing. Ring 29 →
The manual focusing operation is performed in cooperation with the first moving ring 24.

On the other hand, during automatic and manual focusing, the rotation of the gear 79 is transmitted to the rotary ring 29 and also to the gear 80 → gear 82, the pulse plate 83 rotates, and the interrupter 84 causes the lens to move during automatic focusing. A pulse is generated according to the moving amount of L _{1 to} L ₇ . This pulse is used to control the automatic focusing operation.

At the position of the rotating ring 29, that is, the positions of the lenses L _{1 to} L ₇ , the brush 46 attached to the rotating ring 29 via the brush holding plate 47 is provided on the flexible printed board 49 to generate a signal. By sliding on the use pattern, it is detected as a combination of outputs of each bit, and this detection signal is used for various controls.

In the single lens as in the second embodiment,
A configuration in which the ultrasonic motor A is arranged outside the diaphragm unit D and the outside is covered with the fixed cylinder 21 is optimal for reducing the outer shape of the lens barrel.

However, when the flexible printed board 44 provided with the signal generating pattern is attached to the outer diameter surface of the fixed cylinder 21 as in the conventional case, the radial thickness of the brush 26 is increased, and the fixed ring 23 is provided outside thereof. Because it needs to be placed
The lens barrel becomes larger. Although it is conceivable that the flexible printed board 44 is attached to the inner diameter surface of the fixed cylinder 21, the flexible printed board 24 is properly positioned and attached along the inner diameter surface of the cylindrical fixed cylinder 21, and the brush 26 is further attached. Mounting from the inside is very difficult.

Therefore, in the second embodiment, in order to solve these problems, the drive transmission of the flexible printed board 44 provided with the signal generating pattern for detecting the positions of L _{1 to} L ₇ in the focusing operation. It was attached to a signal ground plane 85 extending from the device C in the rotation direction, and the positions of the lenses L _{1 to} L ₇ were detected by the relative positional relationship with the rotation ring 29.

This makes it possible to provide the signal detection device without increasing the outer diameter of the lens barrel. In addition, the assembling procedure is the electric diaphragm device, the first moving ring 24, and the second moving ring 2.
5, the optical unit in which the third moving ring 27 and the rotating ring 29 are combined, and the flexible printed board 44 are attached, and the driving force transmission device C is mainly divided into two units to be assembled. The ring 37 and the roller 30 are removed, the unit is removed, the flexible printed board 44 in the unit is replaced, and the unit, the name ring 37, and the roller 30 are reassembled, which is a relatively simple operation. It is also possible to reduce the possibility of foreign matter mixing in the normal assembly work.

Third Embodiment FIG. 5 is a sectional view of a lens barrel showing a third embodiment of the present invention. In FIG. 5, reference numeral 151 denotes a mount having a claw portion 151a for connecting to the camera body. The mount 151 holds the lens L108, extends forward of the lens, and is a rectilinear ring parallel to the optical axis on the inner diameter side. 151c
Has three legs 151b provided with.

Reference numeral 152 denotes an outer tubular portion 152a and an inner tubular portion 152b.
The outer cylinder portion 152a and the inner cylinder portion 152b are connected to each other by three connecting portions 152c radially provided with respect to the optical axis. In addition, the outer cylindrical portion 152a has three circumferential grooves 152d in the circumferential direction, the inner cylindrical portion 152b has three convex portions 152e and 152f on the outer diameter side, and the inner cylindrical portion has three convex leads. 152g are provided respectively.

Reference numeral 153 is a pin attached to the three legs 151b of the mount 151 and fitted in the circumferential groove 152d of the zoom cam ring 152 in the optical axis direction. The mount 153 and the zoom cam ring 152 are configured to be rotatable only around the optical axis by the pin 153 and the peripheral groove 152d.

Reference numeral 154 is a male helicoid ring, and the convex portions 152e, 15 of the zoom cam ring 152 are provided on the inner diameter side.
It has a cam 154a provided so as to regulate the relative positional relationship between the zoom cam ring 152 and the male helicoid ring 154, and the mount 15 is provided on the outer diameter side.
It has a key portion 154b and a helicoid 154c, which are fitted in the first rectilinear groove 151c and are movable with respect to the mount only in the optical axis direction.

Reference numeral 155 is a front lens barrel which holds the lenses L101 to L103, and a helicoid 155a screwed to the helicoid 154c of the male helicoid ring 154 and a gear portion 155b are provided in the inner diameter portion thereof. There is.
Reference numeral 156 denotes a rear lens barrel that holds the lenses L105 to L107, and the lead 152 of the zoom cam ring 152.
With g inserted, the zoom cam ring 152 and the rear lens barrel 15
6 has a convex portion 156a for regulating the relative positional relationship with the optical axis 6 and a straight groove 156b parallel to the optical axis.

Reference numeral 157 denotes a blade portion 157a and a driving portion 157b.
And an electromagnetic diaphragm 158 composed of a lens L104.
Is a lens barrel which holds the electromagnetic stop 157, and is screwed to the rear lens barrel 156 so as to sandwich the electromagnetic diaphragm 157.

Reference numeral 159 denotes a straight-moving key screwed to the mount 151. The rear-moving lens barrel 156 is fitted in the straight-moving groove 156b so as to be movable only in parallel with the optical axis and extends forward. There is.

Reference numeral 160 denotes a back cover attached to the mount 151 so as to cover the straight-moving key 159, 161 denotes a rubber ring wound around the outer peripheral portion of the zoom cam ring 152, 16
Reference numeral 2 denotes a contact member that is attached to the mount 151 and serves as an electrical contact with the camera body. The contact member 2 has a hole 16 in an annular disk-shaped hard circuit board 163 on which electric components are mounted to form an electric circuit.
The lead contact piece 162a is pierced through 3a, and the hard circuit board 163 is abutted against the step provided on the lead contact piece 162a for soldering.

Reference numeral 164 denotes an autofocus drive unit, which is arranged in a fan shape like the second embodiment, and is fixed to the mount 151 and electrically connected to the hard circuit board 163, although not shown. There is. Reference numeral 165 is an output shaft that outputs the output of the autofocus drive unit 164 as a rotation in front of the lens, and 166 is an output shaft 16.
5 is an output gear that rotates integrally with 5, and is configured to engage with the gear portion 155b of the front lens barrel 155.

167 is a flexible printed board,
The distal end portion connected to the terminal 157c of the electromagnetic diaphragm 157 and arranged in a U shape in the circumferential direction around the optical axis has a rigid circuit board 16
3 is inserted into the connector and electrically connected. 16
Reference numeral 8 denotes a flexible printed board that is connected to the hard circuit board 163 at one end and is attached to the lens front side thrust surface of the autofocus drive unit 164 at the other end. A signal generation pattern is provided.
On the other hand, the zoom cam ring 152 is included in the signal generation pattern.
The brush 169 attached to is configured to be in sliding contact.

The operation of the third embodiment having the above structure will be described below.

(Variable magnification operation) This operation is performed by rotating the zoom cam ring 152 around the optical axis. In this case, the male helicoid ring 154 and the rear group lens barrel 156 are respectively attached to the key portion 1.
54b and straight groove 151c of mount 151, straight groove 15
Since it is movable only in the optical axis direction due to the relationship between 6b and the rectilinear key 159, it moves back and forth in the optical axis direction according to the relationship between the convex portions 152e and 152f and the cam 154a or the lead 152g and the convex portion 156a. At the same time, due to the relationship between the flexible printed board 168 and the brush 169, the lens L
The positions of 101 to L107 can be detected.

(Focusing Operation) By rotating the front lens barrel 155 through the output shaft 165, the output gear 166 and the gear portion 155b by the autofocus and the output from the drive unit 164, the helicoids 154c and 155a are rotated. This can be done by moving the lenses L101 to L103 forward and backward in the optical axis direction.

In the third embodiment, the autofocus drive unit 16 is used to detect the focal length of the zoom lens.
The flexible printed board 168 having a signal generating pattern is attached to the thrust surface of the lens front side of No. 4 and the signal is read by the brush 169 attached to the zoom cam ring. Therefore, as in the second embodiment, the fixed cylinder is used. 1
By simplifying the configuration of 51, the lens barrel can be downsized.

Moreover, it is possible to arrange the focus drive unit 164 and the signal detection device so as to overlap each other in the same phase in the angular direction, and to reduce the occupied area in the angular direction by combining the focus drive unit 164 and the flexible printed board 168. Since it is possible, the remaining space is
U-shaped part of the flexible printed board 167 connecting the hard disk board 163 and the hard circuit board 163 (shape for absorbing the movement of the electromagnetic diaphragm 157 due to the movement of the rear lens barrel 156)
Alternatively, it can be effectively used for housing the driving portion 157b of the electromagnetic diaphragm 157 when the rear lens barrel 156 moves to the mount side. This makes it possible to secure a sufficient amount of movement of the optical system.

The assembling procedure can be divided into two units and assembled as in the second embodiment. Connection, fixed cylinder 151, contact member 16 with hard circuit board 163
2. After mounting the focus drive unit 164 to which the flexible printed board 168 is pasted, the mount unit in which the rectilinear key 159 is assembled, the zoom cam ring 152, the male helicoid ring 154, the front lens barrel 155, the electromagnetic diaphragm 157 and the lens barrel 158. By assembling two units of the lens barrel unit in which the group lens barrel 156 and the brush 169 are assembled and connecting them with each other by the pin 153, a substantially completed state is obtained.

Therefore, by checking the pattern for signal generation provided on the flexible printed board 168 immediately before it is almost completed, the possibility of foreign matter mixing becomes extremely low.

Further, at the time of replacement, it is sufficient to remove the pin 153 and disassemble only the mount unit, so that the replacement work can be performed efficiently.

[0078]

As described above, according to the present invention,
A fixed lens barrel fixed to the camera body, a movable lens barrel movably supported with respect to the fixed lens barrel, and a driving force transmission device provided on the fixed lens barrel or the movable lens barrel. Since the driving force transmission device and the signal generating device arranged in one of the lens barrel and the signal reading device arranged in the other are provided, the degree of freedom in optical design and mechanical design is large, and the assembling is possible. There is an effect that it is possible to provide a lens barrel having a signal detection device in which foreign matter is unlikely to be mixed during the process and parts can be easily replaced.

[Brief description of drawings]

FIG. 1 is a sectional view of a lens barrel showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a lens barrel showing a second embodiment of the present invention.

FIG. 3 is an exploded view of a main part of a lens barrel showing a second embodiment of the present invention.

FIG. 4 is a front view of a main part of a lens barrel showing a second embodiment of the present invention.

FIG. 5 is a sectional view of a lens barrel showing a third embodiment of the present invention.

FIG. 6 is a sectional view of a conventional lens barrel.

[Explanation of symbols]

 2 Fixed cylinder (fixed lens barrel) 3 Zoom ring (movable lens barrel) 8 Holding base (fixed member) 12 Flexible printed board (signal generator) 13 Brush (signal reader)

Claims (1)

[Claims] 1. A fixed lens barrel fixed to a camera body, a movable lens barrel movably supported with respect to the fixed lens barrel, and a drive provided on the fixed lens barrel or the movable lens barrel. A lens barrel comprising: a force transmission device; a signal generation device disposed on one of the driving force transmission device and the lens barrel; and a signal reading device disposed on the other side.