JPH04343310A - Lens barrel containing surface wave motor - Google Patents

Abstract

PURPOSE:To provide the lens barrel using a surface wave motor which does not damage the contact face of a moving body and a fixed body of the surface wave motor, at the time of driving a photographic lens by a manual operation, and to offer the lens barrel which can execute quickly switching of a go-home photographing function and manual focusing mode priority photographing, etc. CONSTITUTION:The lens barrel is provided with a mode selecting means 21 for generating means 21 for generating an electric signal by an external operation, and when the electric signal of a fact for showing a manual focusing mode is generated by the mode selecting means 21, the manual focusing mode is selected, a manual operating means 10 and a fixed body 6 always become turnable integrally, and also, power source supply to a surface wave motor by a power source means 100 is cut, a moving body 9 and the fixed body 6 of the surface wave motor become turnable integrally by its frictional force, and when an electric signal of a fact for showing an automatic focusing mode is generated by the mode selecting means 21, the automatic focusing mode is selected, the power source supply to the surface wave motor by the power source means 100 is executed, and by the surface wave of the fixed body 6, the moving body 9 becomes turnable.

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 photographic lens.

0002

[Prior art] In a lens barrel using a surface wave motor,
Due to the drive principle of a surface wave motor, the rotor (moving body) and stator (fixed body) are strongly pressed together at their contact surfaces.
To manually drive a photographic lens, it is necessary to rotate the rotor with a torque that exceeds the frictional force between the rotor and stator.
As a method for easily manually driving the photographic lens, there is a method of weakening the frictional force between the rotor and stator, or separating the rotor and stator, as disclosed in Japanese Patent Application Laid-Open No. 101608/1983. method is known.

However, in these methods, although the frictional force is weak, in order to rotate the rotor that is in frictional contact with the stator, the contact surface between the rotor and the stator is unnecessarily worn out. Furthermore, when the rotor and stator are separated from each other, dust and the like can enter between them, resulting in damage to the contact surface when the surface wave motor is driven.

In order to solve this problem, when the mode switching means is in the manual focus adjustment mode, the movable body and the fixed body of the surface wave motor are integrated and rotate in conjunction with the operation of the manual operation member. By configuring the photographing lens to be driven, and in automatic focus adjustment mode, the fixed body is fixed to the lens barrel and the photographic lens is driven by the rotation of the movable body, contact between the movable body and the fixed body during manual operation is avoided. A method of driving a photographing lens without damaging its surface is proposed in Japanese Patent Application Laid-Open No. 61-86718.

[0005]

[Problem to be Solved by the Invention] However, the method proposed in Japanese Patent Application Laid-Open No. 61-86718,
By sliding the switching means, the outer cylinder of the surface wave motor and the fixed cylinder can be moved so that the surface wave motor does not rotate within the fixed cylinder even if the lens holding cylinder is driven by the surface wave motor during automatic focus adjustment mode. By sliding the switching means in the opposite direction in the manual focus adjustment mode, the friction force on the contact surface between the manual ring and the outer cylinder is greater than the driving force that drives the lens holding cylinder. Since the camera switches mechanically to the desired shooting distance, a complicated mechanism is required, and if you memorize a desired shooting distance in advance and then take a picture at a different shooting distance, you can change the lens to the memorized shooting distance. A mechanical switching mechanism is used when performing so-called go-home shooting function, or when performing priority shooting in so-called manual focus adjustment mode, which instantly switches to manual focus adjustment mode by rotating the manual operation ring while shooting in automatic focus adjustment mode. Therefore, it is very difficult to incorporate a mechanism for quickly switching the functions.

[0006] The present invention has been made in view of the above-mentioned problems, and involves damage to the contact surface between the movable body and the fixed body of the surface wave motor when manually driving the photographic lens. It is an object of the present invention to provide a lens barrel that uses a surface wave motor without any surface wave motor, and also to provide a lens barrel that can quickly switch between a go-home photography function, a manual focus adjustment mode, and priority photography.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a fixed body (6) capable of generating surface waves;
a surface wave motor having a movable body (9) that is in frictional contact with the fixed body and is rotatable about an optical axis by the surface waves; a power supply means that enables the surface wave motor to operate; a photographing optical system (L2); , L3); a manual operation means (10) which is externally operable and which can drive the photographing optical system by the operation; and a manual operation means (10) which is externally operable and which drives the photographic optical system by the surface wave motor. a mode selection means (20) capable of selectively selecting either an automatic focus adjustment mode in which the photographing optical system is driven by manual operation of the manual operation means; In the cylinder, the mode selection means (20) generates an electric signal by the external operation, and the mode selection means (20) generates an electric signal by the external operation.
20), when an electric signal indicating the manual focus adjustment mode is emitted, the manual focus adjustment mode is selected, and the manual operation means (10) and the fixed body (6)
The movable body (9) and the fixed body (6) of the surface wave motor are made to be able to rotate integrally at all times, and the power supply from the power supply means to the surface wave motor is cut off, and the movable body (9) and the fixed body (6) of the surface wave motor are rotated by their frictional force. When the mode selection means (20) generates an electric signal indicating the automatic focus adjustment mode, the automatic focus adjustment mode is selected, and the surface is rotated by the power supply means. Power is supplied to the wave motor, and the moving body (9) is made rotatable by the surface waves of the fixed body (6).

[0008]

[Operation] According to the lens barrel of the present invention, the fixed body of the surface wave motor and the manual operation member are integrally connected rotatably to the fixed barrel of the lens barrel, and the mode selection means is electrically connected. Only a switch is used, and when the manual focus adjustment mode is selected by the mode selection means, the moving body and fixed body of the surface wave motor are integrated and rotate in conjunction with the manual operation of the manual operation member, thereby driving the photographing optical system. The fixed body is fixed to the lens barrel when the automatic focus adjustment mode is selected, and the imaging optical system is moved by the rotation of the movable body. It becomes possible to drive the photographing optical system without damaging the contact surface between the movable body of the motor and the fixed body. Therefore, for example, switching operations such as a go-home shooting function and a manual focus adjustment mode priority shooting function can be performed using only an electric switch, and it is very easy to incorporate a mechanism for quickly performing the switching operation.

[0009]

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

The fixed lenses L2 and L3 are optical systems for focus adjustment, and are held in a lens holding tube 2, and focus adjustment is performed by moving them in the optical axis direction. Central diameter part 1 of fixed lens barrel 1
A lens holding cylinder 2 is fitted into the inner periphery of a so as to be movable in the optical axis direction. A pin 3 is implanted on the outer periphery of the lens holding barrel 2. The pin 3 is provided in the central medium diameter portion 1a of the fixed lens barrel 1 and passes through a guide groove parallel to the optical axis. It engages with a cam groove 4a provided on the inner peripheral surface of the cam ring 4. The cam ring 4 is fitted into the outer circumference of the central medium diameter portion 1a of the fixed lens barrel 1, and the pin 5 implanted on the outer circumference of the central medium diameter portion 1a is a circle provided on the inner peripheral surface of the cam ring 4. Since it is engaged with the circumferential groove 4b, the cam ring 4 remains stationary in the optical axis direction and is rotatable only through a predetermined angle around the optical axis. In addition, a 4c
A distance scale is displayed. The stator 6 of the surface wave motor M is fitted into the outer periphery of the central small diameter portion 1c of the fixed lens barrel 1 so as to be rotatable about the optical axis, and an engagement protrusion 6a is provided on the outer periphery. The mating protrusion 6a is integrally fixed to the manual operation ring 10 and engages with the mating groove 7a of the intermediate ring 7 made of transparent synthetic resin. The window member 8 is provided on the large diameter portion 1d of the fixed lens barrel 1 and is made of transparent synthetic resin. This window member 8 allows the distance scale displayed on the right large-diameter outer peripheral portion 4c of the cam ring 4 to be read through the intermediate ring 7 made of transparent synthetic resin. The rotor 9 is in frictional contact with the stator 6 and is rotatably provided 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 engages with an engagement protrusion 4d provided on the right large-diameter inner circumferential portion of the cam ring 4, so that the rotor 9 and the cam ring 4 are connected to each other. rotates integrally in the direction of rotation. The manual operation ring 10 is fitted into 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. The biasing member 11 applies a predetermined torque to the stator 6 so that the stator 6 does not easily rotate during the automatic focusing mode. The biasing member 14 brings the stator 6 and rotor 9 into frictional contact via the disk 13. glass epoxy board 1
5 is fixed to the stator 6, and as shown in FIG. 2, a conductor portion 15a is provided on the ring around the entire circumference, so that the brush 16 slides on the conductor portion 15a and the stator Electrical connection to the stator 6 is possible no matter what angular position the stator 6 is in.

A through hole 15b is provided at a position offset from the ring-shaped member from the conductive portion 15a, and the conductor portion communicates with the back surface of the glass epoxy plate 15, and the stator 6 is electrically connected to the conductive portion 15a from the back surface. 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 machine screws 19. The mode selector switch 20 is connected to the fixed lens barrel 1.
When slid in the M direction in Figure 1, the focus mode is manual, and when it is slid in the A direction, the focus mode is automatic, and at the same time it generates electrical signals according to each mode. The structure is as follows. In addition, when sliding in the M direction, that is, in manual focus adjustment mode, the mode selector switch 20 is
The switching plate 21 fixed at 3 also moves at the same time, and the leaf spring 22 fixed to the fixed lens barrel 1 with the machine screw 24 is pushed up as shown by the dotted line in FIG. The leaf spring 22 is released from the plurality of engagement grooves 7b. When the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are disengaged, the manual operation ring 10 is rotatable. When sliding in direction A from manual focus adjustment mode, that is, when in automatic focus adjustment mode, mode selector switch 2
At the same time, the switching plate 21, which is fixed at 0 with machine screws 23, moves, and the leaf spring 22 returns to its initial state as shown by the solid line in FIG. are engaged, and rotation of the manual operation ring 10 is prevented.

Note that if 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 to drive the lens holding barrel 2 is C, then C< B
<Condition A is satisfied. Next, the operation of this embodiment will be explained with reference to FIG. Note that FIG. 3 shows a schematic block diagram of the lens barrel in this embodiment.

- Description of automatic focus adjustment mode In the automatic focus adjustment mode, the mode changeover switch 20 is in the A position, and the engagement groove 7b of the intermediate ring 7 is closed as shown by the solid line in FIG.
Since the plate spring 22 is engaged with the manual operation ring 10, rotation of the manual operation ring 10 is prevented, and the stator 6 is also in a state where it cannot rotate. Here, when power is supplied to the surface 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
rotates in the circumferential direction. When the rotor 9 rotates, the engagement groove 9a on the left side of the rotor 9 engages with the engagement protrusion 4d provided on the cam ring 4, so the rotor 9 and the cam ring 4 are integrated. Rotate to . And cam ring 4
When the lens rotates, the lens holding cylinder 2 moves along the optical axis, and automatic focus adjustment is performed.

- Description of manual focus adjustment mode In the manual focus adjustment mode, the mode changeover switch 20 is slid in the direction M in FIG. As a result, the power supply to the surface wave motor M is cut off. When the mode changeover switch 20 is slid in the M direction, the machine screw 23 is inserted into the mode changeover switch 20.
At the same time, the switching plate 21 fixed to the fixed lens barrel 1 is also moved, and the plate spring 22 fixed to the fixed lens barrel 1 with the machine screw 24 is pushed up as shown by the dotted line in FIG. The plate spring 22 is separated from the engagement groove 7b provided separately. When the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are disengaged, the manual operation ring 10 is rotatable, and since the power supply to the surface wave motor M is cut off, the surface wave motor M is not driven, and the stator 6 and rotor 9 are in a state of being strongly pressed by the biasing member 14. moreover,
The friction torque A between the stator 6 and the rotor 9 and the torque C required to drive the lens holding cylinder 2 satisfy the condition C<A, so when the manual operation ring 10 is rotated, the intermediate ring 7 The stator 6 and rotor 9 rotate integrally through the rotor 9. When the rotor 9 rotates, the engagement groove 9a at the left end of the rotor 9
Since the rotor 9 and the engagement protrusion 4d provided on the cam ring 4 are engaged with each other, the rotor 9 and the cam ring 4 rotate integrally. When the camrel ring 4 rotates, the lens holding cylinder 2 moves in the optical axis direction, and manual focus adjustment is performed.

In this embodiment, the mode changeover switch 20 is in the A position in the automatic focus adjustment mode, and as shown by the solid line in FIG.
are engaged, so rotation of the manual operation ring 10 is prevented, and the stator 6 is also in a state where it cannot rotate. However, the engagement groove 7b of the intermediate ring 7 and the leaf spring 22 are engaged with each other. Even if the stator 6 does not rotate, the friction torque B between the fixed lens barrel 1 and the stator 6 and the torque C required to drive the lens holding barrel 2 satisfy the condition C<B. Instead, only the rotor 9 rotates. In other words, the automatic focus adjustment mode and the manual focus adjustment mode can be easily switched depending on whether or not power is supplied to the surface wave motor M.

Therefore, there is a go-home shooting function in which an arbitrary shooting distance is stored in advance and the lens is driven to the stored shooting distance after shooting at a different shooting distance. Manual focus adjustment mode that instantly switches to manual focus adjustment mode by rotating the camera When performing priority shooting, there is no need to mechanically switch, so it is extremely important to incorporate a mechanism to quickly switch between these functions or modes. It becomes easier.

[0017]

According to the lens barrel of the present invention, the fixed body of the surface wave motor and the manual operation means are integrally connected rotatably to the fixed barrel of the lens barrel, and the mode selection means is electrically connected. When the manual focus adjustment mode is selected by the mode selection means, the moving body and the fixed body of the surface wave motor are integrated and rotate in conjunction with the manual operation of the manual operation member, thereby changing the photographing optical system. When the automatic focus adjustment mode is selected, the fixed body is fixed to the lens barrel, and the photographing optical system is moved by the rotation of the movable body. It becomes possible to drive the photographing optical system without damaging the contact surface between the movable body and the fixed body of the surface wave motor. Therefore, for example, switching operations such as the go-home shooting function and manual focus adjustment mode priority shooting can be performed using only an electric switch, and it is very easy to incorporate a mechanism for quickly performing the switching operations.

[Brief explanation of drawings]

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

[Figure 2] Cross-sectional view of the power supply section in Figure 1

[Figure 3] Schematic block diagram of lens barrel

[Explanation of symbols of main parts]

L2, L3... Focus adjustment optical system L1, L4...Fixed lens 1... Fixed lens barrel 2... Lens holding tube 3... Pin 4... Cam ring 5... Pin 6... Stator 7... Intermediate ring 8... Window components 9... Rotor 10... Manual operation ring 11... Biasing member 12...Bearing 13... Disk 14... Biasing member 15...Glass epoxy board 16...Brush 17... Holding plate 18...Brush fixing plate 19... Machine screw 20...Mode selector switch 21... Switching plate 22... Leaf spring

Claims (1)

[Claims] 1. A surface wave motor comprising a fixed body capable of generating surface waves, and a movable body that is in frictional contact with the fixed body and can be rotated around an optical axis by the surface waves; the surface wave motor is actuable. a power supply means capable of being externally operated and capable of driving the photographing optical system by the operation; a power supply means capable of being externally operated and capable of driving the photographing optical system by the surface wave motor; A lens barrel including a mode selection means that can selectively select either an automatic focus adjustment mode for driving the system and a manual focus adjustment mode for driving the photographing optical system by manual operation of the manual operation means. wherein the mode selection means generates an electric signal by the external operation, and selects the manual focus adjustment mode when the mode selection means generates an electric signal indicating the manual focus adjustment mode; The manual operation means and the fixed body are always rotatable together, and the power supply to the surface wave motor by the power supply means is cut off, so that the movable body of the surface wave motor and the fixed body are free from friction. when the electric signal indicating the automatic focus adjustment mode is emitted by the mode selection means, selects the automatic focus adjustment mode;
A lens barrel with a built-in surface wave motor, wherein power is supplied to the surface wave motor by the power supply means, and the movable body is made rotatable by the surface waves of the fixed body.