JP3134345B2 - Lens barrel with built-in surface wave motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel using a surface wave motor for automatically driving a taking lens.

[0002]

2. Description of the Related Art In a lens barrel using a surface acoustic wave motor,
Due to the driving principle of the surface acoustic wave motor, the rotor (moving body) and the stator (fixed body) are strongly pressed on the contact surface,
In order to manually drive the taking lens, it is necessary to rotate the rotor with a torque exceeding the frictional force between the rotor and the stator,
As a method of lightly driving the photographing lens manually, as in JP-A-59-101608, the frictional force between the rotor and the stator is reduced, or the rotor and the stator are separated from each other. Methods are known.

[0003] However, in these methods, although the friction force is weak, the contact surface between the rotor and the stator is unnecessarily worn to rotate the rotor in frictional contact with the stator. In addition, since the rotor and the stator are separated from each other, dust and the like enter between the rotor and the stator, so that the contact surface is damaged when the surface acoustic wave motor is driven.

In order to solve this problem, when the mode switching means is in the manual focus adjustment mode, the moving body and the fixed body of the surface acoustic wave motor are integrated with each other and are rotated in conjunction with the operation of the manual operation member. When the photographing lens is driven, the fixed body is fixed to the lens barrel in the automatic focusing mode, and the photographing lens is driven by the rotation of the moving body. A method of driving a photographing lens without damaging the surface has been proposed in Japanese Patent Application Laid-Open No. 61-86718.

[0005]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
In the method proposed in JP-A-61-86718, by sliding the switching means, the surface wave motor rotates in the fixed cylinder even when the lens holding cylinder is driven by the surface wave motor in the automatic focusing mode. In order to avoid the friction, a frictional force is generated at the pressure contact surface between the outer cylinder and the fixed cylinder of the surface acoustic wave motor. The mechanical switching is performed so that the frictional force of the lens becomes larger than the driving force for driving the lens holding cylinder, so that a complicated mechanism is required, or an arbitrary shooting distance is stored in advance and another shooting distance is stored. After shooting with, the lens is driven to the stored shooting distance by the so-called go-home shooting function, and the manual focus adjustment is instantaneous by rotating the manual operation ring during shooting in the automatic focus adjustment mode Switch to over-de, for mechanical switching mechanism is required when performing a so-called manual focus adjustment mode priority photography, it is very difficult to incorporate a quickly performed mechanism switching of said function.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to damage a contact surface between a moving body and a fixed body of a surface acoustic wave motor when a photographing lens is driven by a manual operation. It is an object of the present invention to provide a lens barrel using a surface acoustic wave motor, and a lens barrel that can quickly switch between a go-home shooting function and a manual focus adjustment mode priority shooting.

[0007]

According to the present invention, there is provided a photographing optical system (L2, L3), a fixed body (6) capable of generating a surface wave, and frictional contact with the fixed body. Taking and rotates about the optical axis of the imaging optical system by said surface wave
A surface acoustic wave motor having a driver (9) capable of driving a part of the shadow optical system ; power supply means capable of operating the surface acoustic wave motor; and a fixed body (6) fixed to the fixed body (6) and manually operated. To
In the lens barrel with the built-in surface wave motor including the movable manual operation means (10), the fixed body is a part (1) of the lens barrel.
C) is slidably disposed on the driving body.
Is set to be larger than the torque required for
Drive when the fixed body is moved by operating the means
The body can be moved integrally, and the surface wave
Power to the motor, and the driving body is driven by the driving force of the surface acoustic wave motor.
When driven, fixed body (6) and lens barrel (1C)
The manual operation means fixed to the fixed body without sliding
It was configured not to drive .

[0008]

According to the surface wave motor built lens barrel the present invention, the fixed body and the manual operating member of the surface wave motor is rotatably connected with respect to the fixed barrel integrally lens barrel, and the table
Friction torque between fixed body of surface wave motor and fixed barrel of lens barrel
The torque must be greater than the torque required to drive the driver.
You. Therefore, the surface wave motor is operated by the power supply means.
The fixed body is fixed to the lens barrel
Without driving the operating member, the rotation of the driving body
The photographing optical system can be driven,
When the moving operation member moves, the driving body of the surface acoustic wave motor
When the fixed body rotates together, the shooting optical system
It is configured to be driven, so that
When moving the shadow optical system, the
The contact surface with the fixed body is not damaged. Further
The surface wave motor is energized by the power supply
In the course of driving the photographing optical system with the driving force of the motor
Also stops power supply to the surface wave motor by the power supply means
Allows manual operation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a state of an automatic focus adjustment mode in which the focus adjustment optical systems L2 and L3 are driven by the rotating power of the surface acoustic wave motor M, and the mode switch 20 is set to the automatic focus adjustment mode.

The fixed lenses L2 and L3 are held in a lens holding tube 2 by a focus adjusting optical system, and the focus is adjusted by moving in the optical axis direction. Central middle diameter part 1 of fixed lens barrel 1
A lens holding tube 2 is fitted on the inner periphery of the portion a so as to be movable in the optical axis direction. A pin 3 is implanted on the outer peripheral portion of the lens holding barrel 2, and the pin 3 is provided in a central middle diameter portion 1 a of the fixed barrel 1 and penetrates a guide groove parallel to the optical axis. The cam ring 4 is engaged with a cam groove 4 a provided on an inner peripheral surface of the cam ring 4. The cam ring 4 is fitted on the outer peripheral portion of the central intermediate diameter portion 1a of the fixed lens barrel 1, and a pin 5 implanted on the outer peripheral portion of the central intermediate diameter portion 1a is provided on the inner peripheral surface of the cam ring 4. Since the cam ring 4 is engaged with the circumferential groove 4b, it is immovable in the optical axis direction and can rotate only a predetermined angle about the optical axis. Also, 4c is provided on the outer periphery of the right large diameter of the cam ring 4.
Indicates a distance scale. The stator 6 of the surface acoustic wave motor M is rotatably fitted around the optical axis around an outer peripheral portion of the central small-diameter portion 1c of the fixed lens barrel 1, and is provided with an engaging projection 6a on the outer peripheral portion. The mating projection 6a is fixed integrally with the manual operation ring 10, and is engaged with the engaging groove 7a of the intermediate ring 7 formed of a transparent synthetic resin. The window member 8 is provided on the large-diameter portion 1d of the fixed lens barrel 1 and is formed of a transparent synthetic resin. The window member 8 is passed through the intermediate ring 7 made of a transparent synthetic resin and passed through the cam ring 4.
The distance scale displayed on the right large-diameter outer peripheral portion 4c can be read. The rotor 9 is in frictional contact with the stator 6 and is provided rotatably with respect to the stator 6 via a bearing 12. An engagement groove 9a is provided on the left side of the rotor 9 and is engaged with an engagement protrusion 4d provided on the inner periphery of the cam ring 4 on the right side of the cam ring 4. Rotates integrally with respect to the rotation direction. The manual operation ring 10 is fitted to the large diameter portion 1d and the left large diameter portion 1e of the fixed lens barrel 1 and is provided so as to be immovable in the optical axis direction and rotatable about the optical axis. Urging member 11
Is to apply a predetermined torque to the stator 6 so that the stator 6 does not easily rotate in the automatic focus adjustment mode. The urging member 14 is connected to the stator 6 and the rotor 9 via the disc 13.
Is brought into frictional contact with The glass epoxy plate 15 is used for the stator 6
And the conductor portion 15a is provided over the entire circumference on the ring as shown in FIG.
No matter which angular position the brush 16 slides on 15a, the stator 6 can be electrically connected to the stator 6.

A through hole 15b is provided at a position offset from the ring-shaped member from the conductive portion 15a, and a conductor portion communicates with the back surface of the glass epoxy plate 15, from which the stator 6 is electrically connected to the stator 6. It is connected.
The holding plate 17 fixes the brush 16 to the brush fixing plate 18. The brush fixing plate 18 is fixed to the fixed lens barrel 1 with small screws 19. The mode changeover switch 20 is slidably provided on the fixed lens barrel 1. When the slide is made in the direction M in FIG. 1, the mode is set to the manual focus adjustment mode, and when the slide is made in the direction A, the mode is set to the automatic focus adjustment mode. An electric signal is generated according to each mode. Further, when the lens is slid in the M direction, that is, in the manual focus adjustment mode, the switching plate 21 fixed by the small screw 23 to the mode change switch 20 simultaneously moves, and the small screw 24
1 is pushed up as shown by the dotted line in FIG. 1 to release the leaf spring 22 from the plurality of engagement grooves 7b provided on the outer peripheral portion of the intermediate ring 7. When the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are separated, the manually operated ring 10
Becomes rotatable. When sliding in the direction A from the manual focus adjustment mode, that is, in the automatic focus adjustment mode, the switching plate 21 fixed to the mode switching switch 20 with the small screw 23 also moves at the same time, and the leaf spring 22 moves in FIG. It returns to the initial state as shown by the solid line, and the engagement groove 7 of the intermediate ring 7
b and the leaf spring 22 are engaged, and the rotation of the manually operated ring 10 is prevented.

When the friction torque between the stator 6 and the rotor 9 is A, the friction torque between the fixed lens barrel 1 and the stator 6 is B, and the torque required for driving the lens holding cylinder 2 is C, C < B
<The condition of A is satisfied. Next, the operation of this embodiment will be described with reference to FIG. FIG. 3 is a schematic block diagram of the lens barrel in the present embodiment.

Description of the automatic focus adjustment mode In the automatic focus adjustment mode, the mode switch 20 is set to A
1 and the leaf spring 22 is engaged with the engagement groove 7b of the intermediate ring 7 as shown by the solid line in FIG.
The rotation of 10 is prevented, and the stator 6 is also in a state of being unable to rotate. Here, when power is supplied to the surface acoustic wave motor M by a control mechanism not shown (corresponding to the power supply means 100 in FIG. 3), a surface traveling wave is generated in the stator 6 and the rotor 9 is moved in the circumferential direction. Rotate. When the rotor 9 rotates, the engagement groove 9a on the left side of the rotor 9 and the engagement protrusion 4d provided on the cam ring 4 are engaged, so that the rotor 9 and the cam ring 4 are integrated. To rotate. When the cam ring 4 rotates, the lens holding cylinder 2 moves along the optical axis,
Automatic focus adjustment is performed.

Description of the manual focus adjustment mode In the manual focus adjustment mode, the mode switch 20 is slid in the direction M in FIG. As a result, power supply to the surface acoustic wave motor M is cut off. Set the mode switch 20 to M
1, the switching plate 21 fixed to the mode changeover switch 20 with the small screw 23 also moves at the same time, and the leaf spring 22 fixed to the fixed barrel 1 with the small screw 24 is indicated by a dotted line in FIG. As shown, the plate spring 22 is disengaged from the plurality of engaging grooves 7b provided on the outer peripheral portion of the intermediate ring 7. When the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are separated from each other, the manually operated ring 10 is rotatable and the power supply to the surface wave motor M is cut off.
Is not driven, and the stator 6 and the rotor 9 are in a state of being strongly pressed by the urging member 14. Further, the friction torque A between the stator 6 and the rotor 9 and the torque C required for driving the lens holding cylinder 2 satisfy the condition of C <A. The stator 6 and the rotor 9 rotate integrally via the ring 7.
When the rotor 9 rotates, the engagement groove 9a at the left end of the rotor 9
The rotor 9 and the cam ring 4 rotate integrally because the and the engaging projections 4d provided on the cam ring 4 are engaged with each other. When the cam ring 4 rotates, the lens holding cylinder 2 moves in the optical axis direction, and manual focus adjustment is performed.

In this embodiment, in the automatic focus adjustment mode, the mode changeover switch 20 is at the position A, and the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 engage as shown by the solid line in FIG. Therefore, the rotation of the manual operation ring 10 is prevented, and the stator 6 is also in a state of being unable to rotate, but even if the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are not engaged. The friction torque B between the fixed lens barrel 1 and the stator 6 and the torque C required for driving the lens holding cylinder 2 satisfy the condition of C <B, so that the stator 6 does not rotate and the rotor 9 does not rotate. Only rotate. In other words, switching between the automatic focus adjustment mode and the manual focus adjustment mode can be easily performed by whether or not power is supplied to the surface acoustic wave motor M.

Therefore, a go-home photographing function for storing an arbitrary photographing distance in advance and driving the lens to the memorized photographing distance after photographing at another photographing distance, and a manual operation ring during photographing in the automatic focusing mode. Switching to the manual focus adjustment mode instantly by rotating it is not necessary to switch mechanically when performing priority shooting in the manual focus adjustment mode. Therefore, it is very difficult to incorporate a mechanism for quickly switching these functions or modes. It will be easier.

[0017]

According to the lens barrel of the present invention, the fixed body of the surface acoustic wave motor and the manual operation member are provided integrally, and the manual operation is performed.
When the manual operation member is driven by the
The driving light and the fixed body rotate as one,
Drive the surface acoustic wave motor by the power supply means.
When the surface wave motor is operated, the fixed body
The manual operation member is fixed to the lens barrel.
The photographing optical system is driven by the rotation of the driver
The optical system is manually moved.
When moving the surface wave motor,
No damage to the contact surface. Therefore, for example, a switching operation such as a go-home shooting function or a manual focus adjustment mode priority shooting function can be performed only by turning on or off the power to the surface acoustic wave motor, and it is very easy to incorporate a mechanism for quickly performing the switching operation. Becomes

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of a power supply unit in FIG.

FIG. 3 is a schematic block diagram of a lens barrel.

[Description of Signs of Main Parts]

 L2, L3 ... Focusing optical system L1, L4 ... Fixed lens 1 ... Fixed lens barrel 2 ... Lens holding cylinder 3 ... Pin 4 ... Cam ring 5 ... Pin 6.・ ・ Stator 7 ・ ・ ・ Intermediate ring 8 ・ ・ ・ Window member 9 ・ ・ ・ Rotor 10 ・ ・ ・ Manual operation ring 11 ・ ・ ・ Urging member 12 ・ ・ ・ Bearing 13 ・ ・ ・ Disk 14 ・ ・・ Energizing member 15 ・ ・ ・ Glass epoxy plate 16 ・ ・ ・ Brush 17 ・ ・ ・ Pressing plate 18 ・ ・ ・ Brush fixing plate 19 ・ ・ ・ Small screw 20 ・ ・ ・ Mode switch 21 ・ ・ ・ Switch plate 22 ・.. Leaf springs

Claims (1)

(57) [Claims] An imaging optical system; a fixed body capable of generating a surface wave and a frictional contact with the fixed body, the surface wave rotating around the optical axis of the imaging optical system, and the imaging light;
A surface wave motor having a driving body capable of driving a part of a scientific system ; power supply means for activating the surface wave motor; fixed to the fixed body and moving the fixed body by manual operation
In a lens barrel including a possible manual operation means, the fixed body is slidably disposed on a part of the lens barrel.
And the frictional torque of the sliding is required to drive the driving body.
Is set larger than the
When the fixed body is moved by the
The power supply means can be driven integrally, and
Energizes the wave motor, and is driven by the driving force of the surface wave motor.
When driving the driving body, the fixed body and the lens
The hand fixed to the fixed body without sliding with the lens barrel
A lens barrel with a built-in surface wave motor, wherein the moving operation means is not driven.