JPS6186718A - Lens constituting body using surface wave motor - Google Patents

Abstract

PURPOSE:To protect the contacting surfaces of a movable body and a fixed body of a motor from being scrached, by constituting the motor in such a way that the movable and fixed bodies are rotated in one body by means of frictional force under a manual mode and only the movable body is rotated under an automatic mode. CONSTITUTION:Focusing is performed when a convex section 12 on the outer periphery of a holding tube 12 holding an optical system 10 is engaged with the groove 1a of the rotor of a surface wave motor V. When a switching means 20 is moved backward under an automatic mode, the motor V is pressure- contacted with a fixing tube 19 by the force of a spring 15 and surface progressive waves are produced in a rotor, resulting in the rotation of the rotor. When the switching means 20 is moved forward under a manual mode, a rotating body and fixed body are pressed against each other by a forcing means and they rotate in one body by means of the frictional force. Since the movable body and fixed body are not separated from each other in such a way and no dust, etc., get into their contacting surfaces, the contacting surfaces are not scratched and the motor can be constituted in a unit type. Moreover, the lens constituting body can be assembled easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a lens assembly using a surface wave motor that automatically drives a photographic lens.

(Background of the Invention) In a lens structure using a surface wave motor, due to the drive principle of the surface wave motor, the rotor and stator are in strong pressure contact at their contact surfaces. (
It is necessary to rotate the rotor with a torque that exceeds the frictional force between the moving object) and the stator (fixed object), and Japanese Patent Application Laid-Open No. 59-10160 is a method for easily manually driving the photographic lens.
As disclosed in Japanese Patent Application No. 8, etc., methods are known in which the frictional force between the rotor and the stator is weakened, or the rotor and the stator are separated from each other. However, in these methods, in order to rotate the rotor which is in frictional contact with the stator, although the frictional force is weak, the contact surface between the rotor and stator is worn out more than necessary, and the rotor and When the rotor and stator are separated from each other, dirt and the like can enter between the rotor and the stator, and when the surface wave motor is driven, the contact surface may be damaged by the dirt or the like that gets between the rotor and the stator. There was a drawback.

(Objective of the Invention) The present invention has been made by focusing on the above-mentioned problem, and is aimed at preventing damage to the contact surface between the movable body of the surface wave motor and the fixed body when driving the photographing lens by manual operation. The object of the present invention is to provide a lens structure using a surface wave motor.

(Summary of the Invention) When the mode switching means is in the manual mode, 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 lens. In the automatic mode, the fixed body is fixed to the lens structure and the photographic lens is driven by the rotation of the movable body, so that the photographic lens can be moved without damaging the contact surface between the movable body and the fixed body during manual operation. The technical point is that it is driven.

(Example) An automatic focusing lens structure will be described below as an example of the present invention.

Figure 1 shows a focusing optical system (hereinafter referred to as the first optical system).
Reference numeral 10 indicates an automatic mode (hereinafter referred to as A mode) driven by the rotating force of the surface wave motor, and the mode switching means 20 is set to A mode.

The first optical system 10 is fixed to a lens holding tube 12,
A helicoid screw 12a is provided inside the lens holding tube 12, and the helicoid screw 12a is connected to the lens holding tube 18.
It is interlocked with the helicoid screw 18a. Further, on the outside of the lens holding cylinder 12, linear convex portions 12b are provided at several places on the circumference in the optical axis direction, and the rotor 1 of the surface wave motor V
It fits into a straight groove 1a provided in the optical axis direction. Between the outer peripheral surface of the surface wave motor ■ and the inner surface of the fixed cylinder 19,
A ring 14 and a biasing spring member 15 are used to press and fix the surface wave motor jv to the fixed cylinder 19 in the A mode, and a manual ring 17 is used to fix the surface wave motor V to the lens holding cylinder in the manual mode (hereinafter referred to as M mode). An annular ring 13 and a biasing spring member 16 are fitted to the surface wave motor V so as to be slidable in one direction of the optical axis and in the circumferential direction. The mode switching means 20 is formed into an annular ring, and is disposed on the fixed tube 19 so that its outer peripheral surface can be slid in the optical axis direction. Fixed through. This mode switching means 20 is provided with a stopper 21 for fixing the modes when switched to A mode and M mode. This stopper 21 is provided to the mode switching member 20 via a biasing spring 29 in order to fix the mode switching member 20 to the fixed cylinder 19 .

The fixed barrel 19 is fixed to a fixed barrel 27, and the fixed barrel 19 is provided with a stopper 24 for restricting the rotation of the lens holding barrel 12 in the circumferential direction (the amount of movement in the optical axis direction).

The lens holding cylinder 12 is provided with a pin 23 that comes into contact with a stopper 24 . In addition, the lens holding tube 12
A date plate 25 indicating the subject distance is fixed to the frame. 2
6 is a distance scale window. A mount 28 (bayonet mount or screw mount) for attaching the lens structure to a camera or the like is fixed to the fixed barrel 27. 11 is an optical system different from the first optical system 10 (hereinafter referred to as a second optical system).

FIG. 2 shows the M mode state in which the first optical system 10 is driven by the manual ring 17, and the mode switching means 2
0 is set to M mode.

In FIG. 2, only the main parts are shown in solid lines, and the other parts are the same as in FIG.

FIG. 3 shows the surface wave motor V in this embodiment, where 1 is a rotor, 2 is a stator, 3 is a piezoelectric element, 4 is a buffer material, 5 is a thin disk, 6 is a biasing member, 7 is a ball bearing etc., and 8 and 9 are rotor 1 rotatable,
It is an outer cylinder provided so that a stator 2, a piezoelectric element 3, a buffer material 4, a thin disk 5, and an urging member 6 are fixed. That is, in FIG.
A biasing member 6 and a disk 5 are fixedly provided to make frictional contact with the piezoelectric element 3, and a buffer material 4 for efficiently vibrating the piezoelectric element 3, a piezoelectric element 3, and a stator 2 are fixed in this order on the disk 5. are doing. The rotor 1, which is in frictional contact with the stator 2, is provided so as to be freely rotatable with respect to the outer cylinder 8.9 via a bearing 7. The outer cylinders 8 and 9 are connected to the parts 7 and 1.
, 2, 3, 4° 5.6 and are fixedly installed to form a surface wave motor V.

Next, the operation of this embodiment will be explained using FIGS. 1 and 2.

Automatic mode (A mode)> In the A mode, the stopper 21 of the mode switching means 20, which is provided so as to be biased outward in the circumferential direction by the biasing spring member 29, is pushed in, and the mode switching means 20 is moved to the mount 28. By sliding the surface wave motor V (i.e., outer cylinder 9) in the direction of
is set by pressing and fixing the ring 14 to the fixed cylinder 19 using the biasing force of the spring 15. At this time, by moving the mode switching means 20 backward, an automatic focusing control mechanism (surface wave motor) is activated by a mechanism (not shown).
The power supply, etc. (hereinafter referred to as the control mechanism) is activated. The biasing force of the spring 15 is applied to the surface wave motor ■ so that the surface wave motor V will not rotate within the fixed cylinder 19 even if the lens holding cylinder 12 is driven by the surface wave motor ■ based on the control mechanism. It is set so that a frictional force is generated at the pressure contact surface between the outer cylinder 9 and the fixed cylinder 19. Since the surface wave motor V is in pressure contact with the fixed cylinder 19, the outer cylinders 8 and 9 of the surface wave motor are also in a fixed state. Here, power is supplied to the surface wave motor V by a control mechanism (not shown) and a surface traveling wave is generated in the stator 2, so that the rotor 1 rotates in the circumferential direction. Therefore, the rotor 1 rotates with respect to the fixed barrel 19, and the rotation is caused by the rotation of the lens holding barrel 12 and the lens holding fixed barrel 1, which are fitted together so as to be movable in the optical axis direction Cζ.
8 are engaged with each other by helicoid screws 12a and 18a, so that the lens holding cylinder 12 moves back and forth with respect to the lens holding fixed cylinder 18, and focus alignment is performed. Note that when the lens holding cylinder 12 is driven by the rotational force of the rotor 1, the manual ring 17 is
Since it is not in contact with the outer cylinder 8 of the surface wave motor V, the manual ring 17 is in a state unrelated to the operation of the lens holding cylinder 12.

<Manual mode (M mode)> M mode is set by sliding the mode switching means 20 forward. When the mode switching means 20 is slid forward, the ring 14 slides and the spring 15
and 16 are compressed. At this time, the spring 15 is in contact with a part of the fixed cylinder 19, and the spring 16 urges the ring 13 forward. When the ring 13 is urged forward, the outer cylinder 8 of the surface wave motor (2) moves forward until it comes into contact with the manual ring 17. When the mode switching means 20 slides further forward, the stopper 21 is urged outward in the lens structure radial direction by the urging spring member 29 and falls into the hole 19b provided in the fixed barrel 19, fixing the mode switching means 20 to the M mode. be done. At this time, the biasing force of the spring 16 due to the movement of the mode switching means 20 and the ring 14 is such that the frictional force of the contact surface between the manual ring 17 and the outer cylinder 8 is greater than the driving force that drives the lens holding cylinder 12. It suffices if it is set to .Also,
Since the power to the surface wave motor V is turned off by setting the mode switching means 20 to M mode,
The surface wave motor V does not operate, and the rotor l and stator 2 remain strongly pressed by the biasing means 6.

Therefore, the rotor 1 operates integrally with the stator 2 due to frictional connection with the stator 2. Here, when the manual ring 17 is rotated, the surface wave motor (2), which is pressed against the manual ring 17, rotates according to the manual ring 17.

The outer cylinders 8 and 9 fix the stator 2, and the rotor 1 is pressed against the stator 2 and fixed by frictional force, so the rotation of the manual ring 17 is transmitted to the rotor 1. become. The rotation of the rotor l is then transmitted to the lens holding cylinder 12.

At this time, the surface wave motor V and the ring 1 are arranged so that the surface wave motor
A bearing (not shown) or the like is provided between the outer cylinders 8 and 9 by the manual ring 17, so that the outer cylinders 8 and 9 can be smoothly driven. It goes without saying that the surface wave motor V and the ring 13 may be configured to rotate integrally with respect to the ring 14.

By rotating the manual ring 17 as described above, the lens holding cylinder 12 is rotated and focus alignment is performed.

In addition, in the A mode, the lens holding tube 12 is driven by the rotation of the surface wave motor, and in the M mode, the rotor 11 of the surface wave motor, the stator 2, the piezoelectric cable 3, the buffer member 4, the thin disk 5, and the attached In order for the force member 6 and the outer cylinders 8 and 9 to rotate together and drive the lens holding cylinder 12, the frictional force between the outer cylinder 9 and the fixed cylinder 19 must be A, the rotor 1 and the stator 2. The frictional force between the manual ring 17 and the outer cylinder 8 is C, the force required to drive the lens holding cylinder 12 is D, and the torque generated by the surface wave motor is T. In A mode, A>T>D. , and in the M mode, it is necessary to satisfy the condition B>C>D or C>B>D.

As described above, according to this embodiment, in the lens structure using the surface wave motor V, in the A mode, the surface wave motor V
Of the components, only the rotor 1 rotates, the other components are fixed relative to the lens structure, and in the M mode, all the components of the surface wave motor V are integrated, and the manual ring 1
7, and prevents the rotor 1 and stator 2 of the surface wave motor from being separated in the M mode (,
Since the friction force between the rotor 1 and the stator 2 is configured to exceed the driving force of the lens holding cylinder 12, the manual ring 1
7 can drive the first optical system and perform focus alignment, and also has the effect of preventing the contact surface between the rotor 1 and the stator 2 from being worn out or damaged more than necessary. . Furthermore, since the surface wave motor V is constructed in a unit type as shown in FIG. 3, it is possible to adjust the surface wave motor before incorporating it into the lens structure, and the assembly of the lens structure becomes easy. There is an advantage.

In the above embodiment, the optical system to be driven is a focusing optical system, but the optical system driven by a surface wave motor or manually may be an optical system that operates in the optical axis direction or circumferential direction. The present invention is not limited to a focusing optical system. In addition, the outer cylinders 8 and 9 attached to the surface wave motor are
It can also be used as an inner cylinder installed inside the surface wave motor.
In this case, the shape of the rotor 1 may be such that a rectilinear groove in the optical axis direction is provided on the outer periphery of the rotor 1, so that the movement of the rotor 1 and stator 2 is Any mechanism is sufficient as long as it can obtain both the state where the stator 2 is immobile and only the rotor 1 moves.

(Effects of the Invention) As described above, according to the present invention, when the mode switching means selects the manual mode or the automatic mode and performs the focusing operation of the photographing lens, the moving body and the fixed body of the surface wave motor are connected to each other. Since there is no separation between the movable body and the fixed body, there is no chance of dirt or the like getting into the space between the movable body and the fixed body (and the contact surface between the movable body and the fixed body will not be damaged.Furthermore, in manual mode, the movable body and the fixed body Since they are designed to operate integrally, there is an effect that unnecessary wear on the contact surfaces is eliminated.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of an embodiment of a lens structure according to the present invention, and FIG. 3 is a perspective view of a surface wave motor built into the lens structure. (Explanation of symbols of main parts) 1... Rotor (moving body), 2... Stator (fixed body) 8.9... Outer cylinder, ■...・・・・・・
Surface wave motor, 13.14... Circular ring, 17...
...Manual ring, 2o...Mode switching means,

Claims (1)

[Claims] A surface wave motor including a fixed body and a movable body that makes frictional contact with the fixed body; an automatic mode in which the photographic lens is driven by the rotating force of the surface wave motor; and a manual mode in which the photographic lens is driven by manual operation of a manual operation member. When the mode switching means is in manual mode, the movable body and fixed body of the surface wave motor can rotate together due to their frictional force, and the mode A surface wave motor is used, characterized in that when the switching means is in automatic mode, the fixed body is fixed to the lens structure and the movable body can be rotated by surface waves of the fixed body. lens structure.