JP2000056204A - Lens barrel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel by which smooth MF operation is made possible, and a distance measure is easily viewed and where dust is easily removed. SOLUTION: Since the arrangement order of a stator 41 and a rotor 42 and that of an MF ring 91 and a distance scale plate 71 are made similar with respect to the direction of an optical axis AX, the smooth MF operation is made possible wile mechanisms 92, 93 and 94 for linking the MF ring and the stator 41 and the mechanisms 5, 52, 45 and 46 for linking the rotor 42 and the distance scale plate 71 are easily prevented from interfering with each other. Also, the need of observing the distance scale plate 71 through the mechanisms 92, 93 and 94 is eliminated by adopting this arrangement order, and a measure member is observed right below a distance window 12a by arranging it in the vicinity of the outer periphery of a lens barrel, so that the distance measure is easily viewed and the dust in the periphery of the distance scale plate 71 is easily removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel mounted on a camera or the like, and more particularly, to a lens for performing automatic focus detection by driving an ultrasonic motor and rotating the entire ultrasonic motor unit in manual operation. Related to the lens barrel.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional lens barrel. In the figure, an ultrasonic motor 104 is a stator 1
41 and a rotor 142 that comes into pressure contact with the rotor 41. The stator 141 is rotatably fitted to the inner fixed cylinder 113 of the fixed cylinder 101. The rotation of the ultrasonic motor 104 is transmitted to the key 145, and the focusing optical system 122 is moved in the direction of the optical axis AX while rotating by the lead groove 113a provided in the inner fixed cylinder 113. The distance is changed.

When automatically adjusting the focal length, an ultrasonic motor 104 is driven by a control circuit (not shown). Thus, the focusing optical system 122 can be moved by a required amount in the direction of the optical axis AX via the key 145 or the like to realize a focused state. When adjusting the focal length manually, the MF ring 191 is rotated. Since the MF ring 191 is connected to the stator 141 of the ultrasonic motor 104 via the interlocking ring 193 and the key 194, the stator 141 of the ultrasonic motor 104 rotates with the rotation of the MF ring 191.
The rotor 142 also rotates integrally by the holding torque of the ultrasonic motor 104, and the focusing optical system 122 moves in the optical axis AX direction.

[0004] A sliding clutch 192 composed of a wave washer is provided between the MF ring 191 and the interlocking ring 193. For this reason, the rotation of the rotor 1
Even if the MF ring 191 is further rotated with the rotation of the rotor 42 forcibly stopped, the slip clutch 192 slips first, so that the rotor 142 of the ultrasonic motor 104 and the stator 1
41 can be prevented from forcibly sliding over the holding torque.

The position of the focusing optical system 122 in the direction of the optical axis AX and the rotational position of the rotor 142 of the ultrasonic motor 104 have a one-to-one correspondence. Therefore, the outer peripheral surface 14 of the rotor 142
A focusing distance scale is provided at 2a so that the focal length of the lens barrel can be visually recognized. Here, the MF ring 191, the interlocking ring 193, and the stator 141 of the ultrasonic motor 104 do not have a relative positional relationship with the focusing optical system 122.
The position is not fixed at 60 °. Therefore, the interlocking ring 193 needs to be a transparent member.

[0006]

However, the above-mentioned lens barrel has the following problems.
That is, since the interlocking ring 193 must be a transparent member, that is, a plastic member, when the MF ring 191 and the like are made of a metal material, mutual dimensions relatively change due to a temperature change, and the slip of the slip clutch 192 of the MF ring 191. There is a possibility that the torque fluctuates drastically and the MF operation becomes impossible or the motor is damaged. Further, since the distance scale 109 is disposed further back than the interlocking member 193, the interlocking ring 193 is disposed considerably far from the distance window 161 and it is difficult to visually recognize the distance scale with respect to the indication mark. . Further, if dust is mixed in the inner peripheral side of the interlocking ring 193, it becomes very difficult to remove the dust.

Accordingly, an object of the present invention is to provide a lens barrel that enables smooth MF operation, makes it easy to visually recognize a distance scale, and easily removes dust.

[0008]

In order to solve the above-mentioned problems, a lens barrel according to the present invention comprises a drive mechanism for converting the rotation of the rotor of the ultrasonic motor around the optical axis into the movement of the focusing lens in the optical axis direction. A manual ring for moving the focus adjustment lens in the optical axis direction by integrally rotating the rotor and the stator around the optical axis and being interlocked with the stator of the ultrasonic motor; and interlocking with the rotor. And a scale member for displaying the shooting distance, wherein the arrangement order of the rotor and the stator and the arrangement order of the scale member and the manual ring are the same in the optical axis direction.

Here, since the arrangement order of the rotor and the stator and the arrangement order of the scale member and the manual ring are the same in the optical axis direction, a mechanism for interlocking the manual ring and the stator, a rotor and the scale member, And a mechanism for arranging the scale member near the outer periphery of the lens barrel while preventing the mechanisms for interlocking with each other from interfering with each other. This enables a smooth MF operation, facilitates visual recognition of the distance scale, and facilitates removal of dust near the scale member.

In a preferred aspect, the apparatus further comprises a rotating ring that supports the scale member, is connected to the rotor, and rotates around the optical axis with rotation of the rotor.

Here, since a rotating ring is further provided,
The attachment of the scale member is easier than in the case where the scale member is attached to a rotor that is difficult to process, and the manufacture of the entire lens barrel is also easier.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lens barrel according to the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the lens barrel of the embodiment. Note that, in the drawing, the upper half and the lower half have cross sections in different directions.

The lens barrel includes a cylindrical fixed barrel 1 mounted on a camera (not shown). This fixed cylinder 1
Is a rear fixed barrel 11 having a plurality of bayonet lugs 11a formed at a rear end, a front fixed barrel 12 having a distance window 12a formed at a predetermined position, and a lead groove 13a for driving a lens.
And the inner fixed cylinder 13 formed with the same. The fixed cylinder 1 is composed of a plurality of members fastened and integrated by screws or the like, but in this embodiment, it is treated as a single member for convenience of explanation. Note that reference numeral AX in the figure indicates the optical axis of the lens barrel.

The first lens group 21 is fixed to the inner periphery of the front fixed barrel 12 and does not move. The second lens group 22
Is a focusing lens which is fixed to the inner periphery of the movable ring 3 which is guided by the lead groove 13a of the inner fixed cylinder 13 and is movable in the optical axis AX direction.
Move in X direction. The third lens group 23 includes the rear fixed barrel 1
1 is fixed to the inner circumference and does not move. That is, in this lens barrel, the focus state of the camera can be adjusted by changing the focal length only by moving the second lens group 22.

An ultrasonic motor 4 is accommodated in an annular internal space formed by the rear fixed cylinder 11 and the internal fixed cylinder 13. The ultrasonic motor 4 includes a stator 41 which is a fixed portion on the rear side and a rotor 42 which is a rotating portion on the front side.
And The stator 41 is locked to the rear fixed cylinder 11 via a slip clutch 43 made of a wave washer. In other words, if no special load is applied to the stator 41, the stator 41 is not fixed to the rear fixed cylinder 11 or the inner fixed cylinder 1
3, but when a predetermined or more rotational force is applied to the stator 41, the stator 41 rotates with respect to the rear fixed cylinder 11 and the internal fixed cylinder 13. Here, an annular circumferential groove 41a is formed on the inner peripheral side of the stator 41, and the circumferential groove 41a has the same outer diameter as the groove width and has a rear fixed cylinder 11
, The stator 41 rotates around the optical axis AX, but is restricted from moving in the direction of the optical axis AX. That is, the stator 41 is fitted to the internal fixed cylinder 13 so as to be rotatable only.

A plurality of contact points 44a are formed concentrically on the rear end face of the stator 41. These contacts 44a
No matter what the rotational position of the stator 41 with respect to the rear fixed cylinder 11, power, signals and the like are supplied from the brush 44 b provided on the rear fixed cylinder 11 side. The rotor 42 can be relatively rotated at an appropriate timing. The rotor 4
2 is urged rearward by a spring 46 composed of a wave washer and is pressed against the stator 41 with a constant force. Also, at one location on the front end face of the rotor 42,
A key 45 for rotationally driving a rotating ring 5 and the like described later.
Are fixed by fixing pins 46. As will be described later, the key 45 is linked with the second lens group 22, and the rotational movement of the rotor 42 is transmitted to the second lens group 22.

The annular rotating ring 5 is slidably fitted on the outer periphery of the inner fixed cylinder 13. Furthermore, the rotating ring 5
The annular circumferential groove 5a formed on the inner peripheral side of the inner groove 13 is guided by a guide pin 13d having the same outer diameter as the groove width of the circumferential groove 5a and fixed around the inner fixed cylinder 13. As a result, the rotating ring 5 rotates smoothly around the optical axis AX, but its movement is restricted in the optical axis AX direction. The outer circumference of the rotating ring 5 is fixed to the rotor
And a rotating ring 5
Is rotated by substantially the same rotation angle as the rotor 42 with the key 45 that rotates with the rotor 42.

The key 45 extends further forward from the rotary ring 5, and a guide for engaging the pin 31 fixed to the movable ring 3 to guide its movement in the optical axis AX direction is provided at the extended portion. A groove 45a is formed. Here, a plurality of pins 32 (only one is shown in the figure) other than the pins 31 are formed on the outer periphery of the moving ring 3, and these pins 31 and 32 are respectively guided by the lead grooves 13 a. The optical axis AX at a certain angle to the optical axis AX
Move around. The key 45, the pins 31, 32, and the lead groove 13a constitute a driving member that converts rotation around the optical axis AX into movement in the direction of the optical axis AX. That is, when the key 45 and the rotating ring 5 rotate with the rotation of the rotor 42, the pins 31 and 32 can be guided along the lead groove 13a with the rotation, and the moving ring 3 rotates around the optical axis AX. While moving in the optical axis AX direction. Here, since the rotation angle of the rotating ring 5 and the moving amount of the moving ring 3 in the direction of the optical axis AX are in a proportional relationship, the second lens group 22 is moved by an amount corresponding to the rotating angle of the rotating ring 5, that is, the rotor 42. It can be reciprocated in the axis AX direction.

A fixing pin 52 is provided at one position of the rotating ring 5.
Thus, one end of a distance scale plate 71 which is a scale member serving as an index of the focal length of the lens barrel is fixed. The distance scale plate 71 extends forward from the rotary ring 5, and a distance scale is engraved on an outer periphery of a tip portion thereof. Here, the rotation angle of the rotation ring 5 and the second lens group 22
Is proportional to the amount of movement in the optical axis AX direction.
The distance scale plate 71 rotates at a rotation angle corresponding to the amount of movement of the lens group 22. That is, the focal length of the lens barrel can be known by observing the distance scale on the distance scale plate 71 directly below the distance window 12a made of a transparent resin material on which the instruction mark is engraved.

An MF, which is a manual ring for manually adjusting the focal length, is located at an intermediate position of the outer periphery of the lens barrel in the direction of the optical axis AX, that is, between the rear fixed barrel 11 and the front fixed barrel 12.
The ring 91 is rotatably arranged only around the optical axis AX. The MF ring 91 is formed of, for example, a metal material, and is connected to an interlocking ring 93 made of the same material as the MF ring 91 via a spring 92 formed of a wave washer. This interlocking ring 9
3 is locked to the stator 41 of the ultrasonic motor 4 via a connecting key 94 made of the same material as the MF ring 91. When the MF ring 91 is rotated forward and reverse, the holding torque of the stator 41 and the rotor 42 is used. The ultrasonic motor 4 rotates forward and reverse as a whole, and the moving ring 3, that is, the second lens group 22 moves back and forth in the optical axis AX direction via the key 45.

Next, the operation of the lens barrel shown in FIG. 1 will be described. First, a case where the focal length of the lens barrel is automatically adjusted will be described. The ultrasonic motor 4 is driven based on an output from a drive circuit (not shown),
When the key 2 is rotated, the key 45 and the rotary ring 5 are rotated. With the rotation of the key 45 and the rotary ring 5, the movable ring 3, ie, the second lens group 22, can be reciprocated in the optical axis AX direction by an amount corresponding to the rotation angle of the rotary ring 5. At this time, the absolute position of the second lens group 22 can be detected by detecting a signal from an encoder (not shown) that detects the amount of rotation of the rotating ring 5, and the precise focusing of the lens barrel can be detected. Operation becomes possible. next,
A case where the focal length of the lens barrel is manually adjusted will be described. When the MF ring 91 is rotated, the ultrasonic motor 4 rotates as a whole via the annular member 93 and the connecting pin 94. As a result, the movable ring 3, that is, the second lens group 22 is moved via the key 45 fixed to the rotor 42 to the optical axis AX.
Move back and forth in the direction.

In the lens barrel of the above embodiment, the arrangement order of the stator 41 and the rotor 42 and the arrangement order of the MF ring 91 and the distance scale plate 71 are the same in the optical axis AX direction. Mechanism 9 for linking with stator 41
Smooth MF operation can be performed while easily preventing the mechanisms 5, 52, 45, and 46 for interlocking the rotors 2, 93, 94 and the rotor 42 with the distance scale plate 71 from interfering with each other. Moreover, by taking the above arrangement order,
It is not necessary to observe the distance scale plate 71 via the mechanisms 92, 93, 94. That is, this mechanism does not need to be made of a transparent member, and the scale member can be arranged near the outer periphery of the lens barrel and can be observed directly below the distance window 12a, so that the distance scale can be easily recognized. At the same time, it is easy to remove dust near the distance scale plate 71. Furthermore, in this embodiment, since the distance scale plate 71 is attached to the rotating ring 5, the attachment is simpler than the case where the distance scale plate is directly attached to the rotor 42 that is difficult to process.

Although the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment. For example, the arrangement order of the stator 41 and the rotor 42 and the arrangement order of the MF ring 91 and the distance scale plate 71 can be changed to those different from those of the embodiment. Specifically, the stator 41 is arranged in front of the rotor 42, and M
Even when the F ring 91 is arranged in front of the distance scale plate 71, the mechanism for linking the MF ring and the stator 41 and the mechanism for linking the rotor 42 and the distance scale plate 71 are mutually similar, as in the above embodiment. Interference can be easily prevented, smooth MF operation can be performed, and the distance scale can be easily recognized, so that dust near the distance scale plate 71 can be easily removed.

Further, in the above embodiment, the MF ring 91 and the interlocking ring 93 are formed of the same material, but they need not necessarily be formed of the same material. For example, they can be formed of another metal material having a similar thermal expansion coefficient.

The mechanisms 92, 93, 94 for interlocking the MF ring and the stator 41 and the mechanisms 5, 52, 45, 46 for interlocking the rotor 42 with the distance scale plate 71 are also limited to those of the embodiment. Instead, various interlocking mechanisms can be applied.

[0027]

As is apparent from the above description, according to the lens barrel of the present invention, the arrangement order of the rotor and the stator and the arrangement order of the scale member and the manual ring are the same in the optical axis direction. Since there is a mechanism for interlocking the manual ring and the stator, and a mechanism for interlocking the rotor and the scale member, it is possible to prevent the mechanism from interfering with each other, and to arrange the scale member near the outer periphery of the lens barrel. Smooth MF operation becomes possible, and the distance scale is easily visually recognized, thereby facilitating removal of dust.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a cross-sectional structure of a lens barrel according to an embodiment.

FIG. 2 is a diagram illustrating a cross-sectional structure of a conventional lens barrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed cylinder 3 Moving ring 4 Ultrasonic motor 5 Rotation ring 12 Front fixed cylinder 13a Lead groove 21 First lens group 22 Second lens group 23 Third lens group 41 Stator 42 Rotor 45 Key 91 MF ring 93 Interlocking ring 94 Connection Key AX Optical axis

Claims (2)

[Claims] A driving mechanism for converting rotation of the rotor of the ultrasonic motor around the optical axis into movement of the focusing lens in the optical axis direction; A lens barrel comprising: a manual ring for moving the focus adjustment lens in the optical axis direction by integrally rotating about an axis; and a scale member for displaying a shooting distance in conjunction with the rotor. A lens barrel in which an arrangement order of the scale member and the manual ring is the same in an optical axis direction. 2. The lens barrel according to claim 1, further comprising: a rotating ring that supports the scale member, is connected to the rotor, and rotates around an optical axis with rotation of the rotor. .