JP4865272B2 - Control apparatus and optical apparatus using the same - Google Patents

Description

  The present invention relates to a driving device that drives a moving body using a piezoelectric motor, an ultrasonic motor, or the like, and an optical apparatus using the driving device.

2. Description of the Related Art Conventionally, in an optical device such as a camera or an interchangeable lens, a driving force generating means such as a motor is used for lens focus driving, zoom driving, or aperture driving. In addition, the moving amount, position, or speed of the focus lens, zoom lens, or diaphragm that is a moving body is detected using an encoder. The output signal of the detection means is left as it is or is electrically processed, and then input to the control means (control circuit board, etc.) for controlling the driving force generation means and other equipment operations via the signal line (communication line). The
The inventor made an optical device using a driving force generating means similar to a piezoelectric motor or an ultrasonic motor as described in Patent Document 1 as the driving force generating means. This driving force generating means excites vibration in the vibrating body by electro-mechanical energy conversion, and relatively drives the vibrating body and the contact body in contact with the vibrating body.
Japanese Patent Laid-Open No. 62-118780

With the recent digitalization, high precision of autofocus is required due to product needs. Therefore, it is essential to increase the resolution of the position detection means for detecting the moving amount (or position / velocity) of the moving body in this type of optical apparatus.
However, in the above-described prototype, even if an output signal from an encoder serving as a position detection means is divided into signals to increase the resolution, the problem is that it is actually difficult to obtain a higher resolution than before the signal division. Occurred.
An object of the present invention is to provide a drive device that can actually increase the resolution by dividing the output signal of the position detection means.

In order to solve the above-mentioned problems, a drive device according to the present invention is arranged on a ring-shaped vibrating body and the ring-shaped vibrating body, and is electrically-excited to vibrate the ring-shaped vibrating body by electro-mechanical energy conversion. and a contact member in contact with the vibrator and mechanical energy conversion element, the electro - and driving force generating means for contacting body and are moved relative to contact with the vibration member and said vibrating member by driving the mechanical energy conversion element a moving member moved in the predetermined direction by the driving force generating means, detecting means for detecting the amount of movement of the moving member, the electricity based on the moving amount detected by said detecting means - mechanical energy conversion element in the driving device and a control means for controlling the electro - mechanical energy conversion element, in the circumferential direction across the ground pattern formed on the ring-shaped vibrating body on Is location, and the portion passing through the vicinity of the vibrating body in the output signal lines from the detection means, and the ground pattern, a line connecting the center of the ring-shaped vibrating body are wired so that the straight line It is characterized by that.

The reason why it was difficult to obtain high resolution accuracy before the signal division in the prototype was that the influence of the noise by the vibrating body of the driving force generating means was significant.
According to the present invention, the portion of the output signal line from the movement amount (or position or velocity) detection means that passes through the vicinity of the vibrating body includes the portion, the ground of the pattern formed on the vibrating body, and the Wiring is performed so that the line connecting the center of the vibrating body is a substantially straight line . Thereby, the influence of noise from the vibrating body of the driving force generating means on the output signal of the moving amount (or position or speed) detecting means is reduced, and an accurate signal is input to the signal dividing means or the control means. Is done.
In addition, when the signal dividing unit receives a signal with reduced influence of noise, accurate high division is possible, and a moving body such as an optical system can be driven with higher accuracy.

In the best mode for carrying out the present invention, the present invention is applied to an optical apparatus such as a camera lens. This optical apparatus includes a driving force generating means for driving the optical system in the optical axis direction. The driving force generating means is configured using a vibration type driving device that excites vibrations in the vibrating body by electro-mechanical energy conversion and relatively drives the vibrating body and a contact body that contacts the vibrating body. In addition, the optical apparatus includes detection means for detecting the amount of movement of the optical system in the optical axis direction, and signal dividing means for making the output signal from the detection means high resolution. And a control means for controlling the driving force generating means in accordance with an output signal from the signal dividing means or an output signal from the detecting means. Furthermore, a communication line is provided for inputting a signal output from the detection means to the control means or the signal dividing means. When the communication line passes near the vibrating body of the driving force generating means, the line connecting the communication line , the ground of the pattern on the vibrating body, and the center of the vibrating body is substantially straight. Perform wiring. Thereby, noise from the vibrating body is reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Example 1]
1 to 4 show an interchangeable lens (zoom lens) for a single-lens reflex camera according to an embodiment of the present invention. In the different drawings, members with the same number represent the same member.
FIG. 1 is a side view at the WIDE end of a zoom lens according to an embodiment of the present invention, and FIG. 2 is a side view at the TELE end. 3 is a cross-sectional view at the WIDE end, and FIG. 4 is a cross-sectional view at the TELE end. FIG. 5 shows the flexible printed wiring board described in FIG. FIG. 6 is a diagram showing the positional relationship between the movement amount detecting means (sensor), the driving force generating means, the printed circuit board, and the flexible wiring board. FIG. 7 is a diagram showing the pattern of the vibrating body (stator) of the driving force generating means and the position of the flexible wiring board.

First, the configuration of the lens barrel will be described with reference to FIGS.
This lens barrel is a zoom lens having a focal length range of 24 mm to 105 mm. By rotating the zoom operation ring 7, the cam ring 30 is rotated at a fixed position with respect to the guide cylinder 29 (parts constituting the fixed portion). The focal length changes. L1 to L7 respectively represent lens groups, and each group is fixed to the same lens barrel and moves as shown below.
That is, the first group lens L1 is held by the first group lens barrel 19, and the first group lens barrel 19 is integrated with the filter frame (movable tube) 1 with screws (not shown). The filter frame 1 is fixed to the rectilinear cylinder 24 with screws (not shown). The rectilinear cam follower integrally fixed to the rectilinear cylinder 24 enters the rectilinear groove provided in the guide cylinder 29 and the cam groove provided in the cam ring 30, so that the optical axis is rotated along with the rotation of the cam ring 30. The focal length is changed by moving forward in the direction.
The abutting surface between the first group barrel 19 and the filter frame 1 is an end cam, and the position in the optical axis direction can be adjusted by rotating the first group barrel 19 before being fixed with screws. It has a configuration.

The second group lens L2 is held by the second group lens barrel 27. A cam follower portion (not shown) and a key interlocking portion 27a are formed on the outer peripheral portion of the second group lens barrel 27, and the inner cam 28a of the focus cam ring 28, the focus key 40a in the focus unit 40, and Each fits and slides. When the focus key 40a rotates as an output of the focus unit 40, the second group lens L2 moves in the optical axis direction while rotating due to the relationship between the cam 28a and the cam follower portion described above. This lens barrel is an inner focus lens, and has a configuration in which the amount of extension of the second group lens L2 for focus adjustment differs depending on the focal length. That is, the above configuration is realized by changing the use position of the focus cam 28a according to the focal length.
The focus cam ring 28 is integrated with the focus cam ring 28 in the interlocking groove in the optical axis direction of the cam ring 30 and the correction cam provided in the guide tube 29 in order to correct the position of the second group lens L2. Cam follower slides. Thereby, the focus cam ring 28 advances and retreats in the optical axis direction while rotating together with the cam ring 30. The second group lens L2 can be moved to a position where no focus position deviation occurs even if the use position of the focus cam 28a is changed depending on the focal length.

The third group lens L3 is held by the third group lens barrel 32, and the sub-aperture unit 31 is fixed to the front side (subject side) of the third group lens barrel 32.
The fourth group lens L4 is held by a fourth group lens barrel 34. A diaphragm unit 33 that determines the aperture diameter of the lens barrel is fixed to the front side, and three connecting legs extend equally to the rear side (image surface side). ing. A seventh group barrel 36 is fixed to the tip of the foot with a screw (not shown). Further, a third group barrel 32 is fixed to the front end face of the fourth group barrel 34, and three cam followers are integrally fixed to the outer peripheral surface equally. This cam follower slides in a cam groove provided in the cam ring 30 and a straight advance groove provided in the guide tube 29, and the three lens groups L3, L4, and L7 are integrated with the rotation of the cam ring. In the direction of the optical axis. Further, the rotating member in the sub-aperture unit 31 is rotated by the cam provided in the guide cylinder 29, and the aperture diameter of the sub-aperture changes depending on the focal length so that there is no F-number fluctuation.

The fifth group lens L5 is a shift group and is held by a lens barrel that constitutes the image stabilization unit 35, and is held on the vertical plane of the optical axis so that it can be freely moved (shifted) by driving means inside the image stabilization unit 35. Has been. A sixth group lens barrel 35a is fixed by three screws 35b on the rear side (image plane side) of the fixed portion in the image stabilizing unit 35. Three cam followers (not shown) are fixed to the outer peripheral portion of the vibration isolation unit 35 and slide in the cam groove of the cam ring 30 and the straight advance groove of the guide tube 29, respectively. The two lens groups L5 and L6 have an optical axis. It moves in the direction as the cam ring rotates. In addition, the multilayer FPC (flexible printed wiring board 102 (refer FIG. 8)) which concerns on the principal part of this invention is fixedly hold | maintained at the front side of the anti-vibration unit 35. Details are mentioned later. Since detailed control is known, detailed description in this embodiment is omitted.
The seventh group lens L7 is held by the seventh group lens barrel 36, and is fixed to the rear end of the connecting foot of the third group lens barrel 34 as described above.

  In each lens barrel of the optical system described above, when the photographer rotates the zoom ring 7, the cam ring 30 is rotated together by an interlocking key (not shown), and each lens group is advanced and retracted in the optical axis direction. The cam ring 30 is bayonet-coupled to the guide tube 29 and rotates at a fixed position with respect to the guide tube. The guide tube 29 is a fixed part of the lens barrel, and is fixed integrally with the fixed joint tube 5, the outer ring 8, and the mount 9 for mounting on the camera. Reference numeral 17 denotes a back pig, which prevents internal reflection in the lens barrel. Reference numeral 10 denotes a sealing rubber, which is configured so that the mount 9 comes into contact with the camera when the lens barrel is mounted on the camera, and can exhibit waterproof and drip-proof performance near the mount. Reference numeral 16 denotes a contact block that performs communication with the camera side, and is connected to a main mounting board 37 on which a CPU that controls the lens barrel is mounted by an FPC 38.

  Reference numeral 40 denotes a focus unit composed of a so-called ultrasonic motor, which is fixed to the guide tube 29. A fixed cylinder 23 is fixed near the distal end of the fixed portion of the focus unit 40, and two vibration gyros 43 serving as vibration detection means are held in a space between the fixed cylinder 23 and the focus unit 40 so as to surround the periphery. Yes. Such an arrangement eliminates the influence of disturbances such as noise. The vibration gyro 43 is connected to the main mounting board 37 by an FPC (not shown) and controls the vibration isolation unit 35 based on a detection signal. The focus ring 3 is disposed between the front end surfaces of the fixed cylinder 23 and the fixed joint cylinder 5, and the rear end portion of the focus ring 8 is fitted to a connecting portion in the focus unit 40. By rotating the focus ring 8, the above-mentioned focus key is rotated to advance and retract the second group lens L2 in the optical axis direction so that manual focusing can be performed. The focus ring 3 has an entire circumferential groove 3a in the inner circumferential portion, and is regulated in the optical axis direction by fitting and sliding the rollers 25 provided at three places on the circumference. The three rollers 25 are fixed to the fixed cylinder 23 by screws 26.

Reference numerals 4 and 6 denote operation rubbers which respectively enter the grooves of the focus ring 3 and the zoom ring 7 to improve the operational feeling. Reference numeral 39 denotes a sheet on which a distance scale is printed, which is fixed on a rotary ring to which a focus key is fixed, and can be confirmed by a photographer through a window 11 arranged on the fixed joint cylinder 5.
Reference numeral 14 denotes a switch panel, which is fixed on the fixed joint cylinder 5 and has a switch for switching the control of the lens barrel. The focus changeover switch 12 can switch between manual focus using the focus ring 3 and autofocus by ultrasonic motor drive. The IS switch 13 is a switch for switching on / off of the control of the above-described image stabilization unit 35.

In addition, this lens barrel has waterproof and drip-proof performance as a whole of the lens barrel by applying sealing members 41 and 42 and waterproof and drip-proof oil as necessary to each operation unit as a waterproof and drip-proof structure. It is like.
Further, as can be seen by comparing FIG. 3 and FIG. 4, in the optical system constituting the lens barrel, all the groups move in the optical axis direction by the zooming operation.

Next, the driving force generating means will be described.
FIG. 5 is an enlarged view of a focus unit using an ultrasonic motor as an example of the driving force generating means. FIG. 6 is a drive signal input pattern diagram on the vibrating body (stator) 105 of the ultrasonic motor.
The stator of this ultrasonic motor includes a ring-shaped vibrating body 105 having electro-mechanical energy conversion elements 107 and 108 on one end surface. The vibrating body 105 is held by the holding ring 113 via the vibration absorbing body 114 at the end face. The rotor of the ultrasonic motor includes a contact body 104 arranged in a ring shape that is in press contact with the other end surface of the vibrating body 105 and a cylinder 115 having a flange. The contact body 104 is held by a pressing ring 112. The cylinder 115 is coupled to the pressing ring 112 at one end and has the flange at the other end.

  In FIG. 6, a large number of electro-mechanical energy conversion elements such as electrostrictive elements are bonded to one end face of a ring-shaped elastic vibrator 105 constituting the stator. Further, the ring-shaped contact 104 constituting the rotor is pressed against the other end surface of the vibrating body 105. A large number of electrostrictive elements are arranged in the circumferential direction of the vibrating body 105, and the group consisting of the electrostrictive elements 107 and the group consisting of 108 are shifted from each other by ¼ of the wavelength λ of the vibration wave generated in the vibrating body 105. Has been placed. In each group, the electrostrictive elements are arranged at a pitch of 1/2, and are arranged so that the polarities of neighboring elements are reversed. Electrode films are provided on the front and back of each electrostrictive element 107, 108 so that an alternating voltage can be applied to each electrostrictive element.

An alternating voltage of the same frequency having a time phase difference of 90 ° is applied to the first group of electrostrictive elements 107 and the other group of electrostrictive elements 108. Then, standing waves are generated in the vibrating body 105 by the electrostrictive elements of each group. As described above, each group is spatially shifted by λ / 4 and is about 90 ° in time. Since excitation is performed with a phase difference, a bending vibration wave traveling in the circumferential direction is generated in the vibrating body 105 as a result of the synthesis of these standing waves. In this bending vibration traveling wave, the points on the neutral plane of the vibrating body 105 in the vertical direction only vibrate in the vertical direction, but the points on the upper surface and the lower surface of the vibrating body 105 are in the vertical direction and the circumferential direction. A kind of elliptical vibration is synthesized.
Accordingly, the contact body 104 that is in press contact with the upper surface of the vibrating body 105 is driven so as to move along the forward direction of the vibrating body 105 by the frictional force at the contact portion. In addition, in the ultrasonic motor, means for pressing and holding the vibrating body and the contact body in the axial direction is necessary to generate a driving force in the motor. Therefore, a pressing force is generated by the nine pressing rings (springs) 112. This is the driving principle of the ultrasonic motor.

Next, details of the focus unit 40 will be described.
FIG. 8 shows a flexible printed wiring board in the sectional view of the lens barrel shown in FIG. In this figure, 101 is a movement amount detecting means (sensor), 102 is a flexible printed wiring board (hereinafter referred to as flexible board 102) for transmitting a signal of the movement detecting means to the control means or signal dividing means, and 37 is a control means (CPU). And a printed circuit board on which signal dividing means (IC) is mounted, 105 is a vibrating body (stator) of driving force generating means (ultrasonic motor), 104 is a contact body (rotor) of driving force generating means (ultrasonic motor), 106 Is a flexible printed wiring board (hereinafter, flex 106) for applying an AC voltage from the control means to the vibrating body of the driving force generating means.

As described above, the AC voltage having a 90 ° phase shift is applied to the electrostrictive elements 107 and 108 when the driving force is generated with the input signal pattern as shown in FIG. The electrostrictive element 110 converts the vibration state of the vibrating body (stator) 105 into an electric signal and transmits it to the control means. Reference numeral 109 denotes a ground (GND) pattern. During driving, the signal is applied to the vibrating body (stator) 105.
For this reason, an AC voltage is applied to the electrostrictive elements 107 and 108 while the driving force generating means is being driven. Therefore, if the flexible cable 102 passes through this area, it will be affected by noise. FIG. 9B shows the difference between when the sensor signal is noisy (broken line) and when it is normal (solid line). Therefore, in order to reduce this influence, wiring of the flexible cable 102 is performed as shown in FIG.

FIG. 7 shows the positional relationship between the vibrating body (stator) 105, the printed circuit board 37, the sensor 101, the flex 102, and the flex 106 extracted from FIG. The analog signal (or pulse signal) output from the optical sensor 101 is input to the control means or signal dividing means on the printed circuit board 37 by the flex 102 shown in FIGS. When wiring the flexible cable 102, wiring is performed so as to pass near the GND 109 (FIG. 6) on the pattern of the vibrating body (stator) 105 described above. That is, the wiring is performed so that the line connecting the flex 102, the GND 109, and the center of the ring-shaped vibrating body 105 is a substantially straight line. Various input patterns of the vibrating body (stator) 105 shown in FIG. 6 can be considered. At this time, the flexible wire 102 is wired near the GND of the stator.

Next, a method for controlling the driving force generating means will be described.
FIG. 10 shows a circuit example of the control means formed on the printed circuit board 37.
In the figure, when driving an ultrasonic (vibration wave) motor, the microcomputer 51 operates the DCDC converter unit 52 to boost the voltage of the power supply 53. In general, the voltage is boosted about 5 times here. Next, the microcomputer 51 activates an internal frequency generator circuit to generate an output in which the phase is changed by ± 90 ° to the A phase and the B phase. This output controls the four transistors of the drive IC 55 that are bridge-connected. For example, transistors connected to the output of the DCDC converter unit 52 are first and third transistors, and transistors connected to GND are second and fourth transistors. Further, it is assumed that the A-phase coil 61 is connected to the connection point between the first transistor and the second transistor, and the B-phase coil 62 is connected to the connection point between the third transistor and the fourth transistor. When the A-phase logic voltage output from the microcomputer 51 is high level, the output logic of the inverter 55 is Lo level, the first transistor is OFF, the second transistor is ON, and the voltage applied to the A-phase of the vibration wave motor is low. Become. Conversely, when the A-phase logic voltage output from the microcomputer 51 is 0 V, the output logic of the inverter 55 is Hi level, the first transistor is ON, the second transistor is OFF, and the voltage applied to the A-phase of the vibration wave motor is Get higher.
With these operations, a drive signal from the CPU 51 is input to the electrostrictive elements 107 and 108 of the vibrating body 105 at a voltage boosted by DCDC by the drive IC 55. The flex 106 in FIGS. 6 and 7 is the drive signal line.
When a voltage is input, the ultrasonic motor starts to start at a specific frequency according to its characteristics.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.
For example, in the above-described embodiments, an example in which the present invention is used for lens focus driving has been described. However, the present invention may be used for zoom driving or diaphragm driving. In addition, an optical sensor is used as the detection means, and the analog signal is put on the output signal line (communication line) as it is, but the output of the detection means is shaped, or the signal divided and pulsed is used as the output signal line. You may make it ride. The detection means may be other means such as a magnetic encoder.
In the above description, an example in which the output of the detection unit is signal-divided has been described. However, the present invention can be applied even when signal division is not performed. In this case, the resolution does not increase, but the detection accuracy of the zero-cross point or the like, that is, the detection accuracy of the movement amount or the like is improved within the same resolution.

It is a side view of WIDE of the lens barrel which concerns on one Example of this invention. It is a side view of TELE of the lens barrel of FIG. It is sectional drawing of WIDE of the lens-barrel of FIG. It is sectional drawing of TELE of the lens-barrel of FIG. FIG. 2 is an enlarged view of a focus block of the lens barrel in FIG. 1. It is a figure which shows an example of the drive signal input pattern on the vibrating body (stator) in FIG. FIG. 2 is a layout diagram of a movement amount detection unit (optical sensor), a printed board, a vibrating body (stator), and a flexible printed wiring board (communication line) in FIG. 1. It is sectional drawing of TELE which shows the state which attached the flexible wiring board to the lens-barrel of FIG. FIG. 2 is a drive voltage waveform applied to a vibrating body (stator) in FIG. 1 and an output waveform diagram of an optical sensor. It is a block diagram which shows the structure of the control means on the printed circuit board in FIG.

Explanation of symbols

37: Printed circuit board 101: Optical sensor 102: Flexible printed circuit board (communication line)
104: Vibrating body (stator)
105: Contact body (rotor)
106: Flexible printed circuit board (drive signal line)
109: GND

Claims (5)

A ring-shaped vibrating body, an electro-mechanical energy conversion element that is disposed on the ring-shaped vibrating body and excites vibration in the ring-shaped vibrating body by electro-mechanical energy conversion, and a contact body that contacts the vibrating body a, the electric - moving member and the contact member in contact with said vibration member and said vibrating member by driving the mechanical energy conversion element which is moved with the driving force generating means for relative movement in a predetermined direction by the driving force generating means When a detection means for detecting a moving amount of the moving member, the electricity based on the moving amount detected by said detecting means - in a drive device and a control means for controlling the mechanical energy conversion element,
The electro-mechanical energy conversion element is arranged in a circumferential direction across a ground pattern formed on the ring-shaped vibrating body,
Wherein a portion passing through the vicinity of the vibrating body in the output signal lines from the detection means, and the ground pattern, that the line connecting the center of the ring-shaped vibrating body are wired so that the straight line A drive device . The ground pattern is formed at two locations on the ring-shaped vibrating body across the center of the ring-shaped vibrating body,
The electro-mechanical energy conversion element is disposed in each of two regions formed by ground patterns formed at two locations on the ring-shaped vibrating body. Drive device. The drive device according to claim 1 or 2, wherein an output signal of the detection means is an analog signal. 3. The driving apparatus according to claim 1, wherein the output signal of the detection means is a pulse signal. An optical apparatus using the drive device according to any one of claims 1 to 4 as drive means for driving an optical system in an optical axis direction.

Images