JPH0880073A - Oscillatory wave motor controller - Google Patents

Abstract

PURPOSE: To improve the control property in repeat start by changing a traveling wave oscillation generated on the surface of an oscillator over to a stationary wave oscillation when the quantity of residual drive of an oscillatory wave motor has become smaller than a specified value, and retaining its stationary wave oscillation in case the next drive is anticipated subsequent to a stop of drive. CONSTITUTION: In an embodiment applied to a single-lens reflex camera, a controller is equipped with a microcomputer 1 on the side of a lens, photointerpreters 2 and 3, which measure the amount of shifting of a focus lens and the amount of shifting of a variable-power lens, and oscillatory wave motor drive circuits 4 and 5. And, this controls the drive of an oscillatory wave motor for focus consisting of a stator 35 and a rotor 36 and the drive of an oscillatory wave motor for variable power consisting of a stator 24 and a rotor 25. Here, the start response property in case of starting the oscillatory wave motor continuously is improved by controlling each oscillatory wave motor so that it may maintain stationary wave mode during the specified time after stoppage of drive by the soft processing of the microcomputer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration wave motor controller.

[0002]

2. Description of the Related Art Vibration wave motors have low rotation and high torque.
It has been practically used for autofocus drive of cameras and the like because it has almost no driving noise and very quick response of start and stop. On the other hand, in a video lens, it is widely practiced to perform so-called power zooming with a motor, and it is needless to say that a vibration wave motor can also be applied to this driving.

In the case of a moving image such as a video, the effect of a continuous change in the angle of view is important, and therefore a power zoom capable of being smoothly driven by using a motor is an essential function. Also,
In the case of video shooting, generally, recording is performed at the same time as recording, so it can be said that it is very advantageous to use a vibration wave motor with almost no operating noise for zoom driving. Recently, power zoom lenses have come to be widely used in still cameras using silver salt films.

The structure of the zoom lens will be briefly described below. In general, the zoom lens needs to move a plurality of lenses in a complicated manner to perform aberration correction and focus movement correction associated with changes in the focal length. Uses a cylindrical cam in which a locus of each moving lens is cut out in a cylinder, and by rotating the cam, each lens is moved to a desired position for correction.

However, as the zoom lens has a higher magnification,
It becomes difficult to correct aberrations and focus movement mechanically,
Especially, the focus movement due to zooming has been a problem in the past.

On the other hand, since autofocus driving a focusing lens by a motor has become common these days, the idea of correcting the focus movement by zooming is further developed to simplify a complicated zoom cam and to reduce aberration fluctuations generated there. The focus movement is also corrected by electrically driving a focusing lens and an aberration correction lens.

[0007]

However, in order to electrically trace a mechanical cam, it is necessary to perform very fine control, and the driving direction of the focusing lens may be reversed during zooming. appear. FIG. 7 is a diagram showing this state. In FIG. 7, the horizontal axis represents the focal length, the left side is the long focal side (tele), the right side is the short focal side (wide), and the vertical axis is the vertical axis. The moving amount of the focusing lens is shown in the figure.
r), the bottom shows the near direction. Eg te
The movement of the focusing lens when zooming from le to wide initially decreases toward the close-up distance side, but the amount of change decreases, and the movement direction reverses at the intermediate zoom position, and further toward the wide side, toward the infinity side. To move to.

The solid line in the figure shows the ideal following position of the focusing lens. On the other hand, when the focusing lens is made to follow using a motor, the drive will eventually end at the target position, but as shown by the dotted line in the figure, it will slightly follow the ideal drive curve during drive. A delay occurs, and the operation of correcting this is always performed.
In particular, since it takes a long time to start the motor at the start of driving, the tracking at the point a where the motor first starts and the point b after the driving direction is reversed becomes poor, and the image is blurred in the viewfinder, which is unsightly. There was a problem to say. This occurs even when using a vibration wave motor with good followability.

In the figure, the upper trace locus shows the trace locus of the focusing lens when the focusing lens is infinitely started, and the lower trace locus shows the trace locus when the focusing lens is very close. .

As a proposal for improving the starting characteristics of a conventional vibration wave motor, Japanese Patent Laid-Open No. 59-106886 discloses that
It has been proposed to drive the vibration wave motor with a standing wave before starting, but this prior art also has a problem that it cannot be applied when the driving direction is frequently reversed or when the driving direction is stopped and then immediately started. It was

[Object of the Invention] An object of the present invention is to cause the vibration wave motor to follow the drive signal with high responsiveness to the drive signal even when the drive direction is continuously reversed or when the drive is repeatedly started. It is an object of the present invention to provide a vibration wave motor control device that can perform Specifically, the purpose of the invention of each claim is clarified as follows.

According to the invention of claim 1, in a vibration wave motor control device for controlling a vibration wave motor having a vibrator for causing traveling wave vibration on a surface by an electro-mechanical energy conversion element, the vibration wave motor is provided. Remaining drive amount calculation means for calculating the remaining drive amount, determination means for determining from the output of the remaining drive amount calculation means that the remaining drive amount has become smaller than a predetermined value, and Vibration switching means for switching the traveling wave vibration to the standing wave vibration according to the output of the discrimination means, and a vibration generation time control means for controlling the generation time of the standing wave vibration. An object of the present invention is to provide a vibration wave motor control device.

According to a second aspect of the present invention, there is provided a vibration wave motor control device for controlling a vibration wave motor comprising a vibrator which causes traveling wave vibration on a surface by an electro-mechanical energy conversion element. Remaining drive amount calculating means for calculating the remaining drive amount of, the comparing means for comparing the remaining drive amount calculated by the remaining drive amount calculating means with a predetermined value, and the vibration generated on the surface of the vibrator by the comparing means. It is an object of the present invention to provide a vibration wave motor control device characterized by having a vibration switching means for switching the traveling wave vibration to the standing wave vibration in accordance with the output of the.

[0014]

In order to solve the above-mentioned problems, the invention of claim 1 provides a vibration wave motor comprising a vibrator which causes traveling wave vibration on the surface by an electro-mechanical energy conversion element. In the vibration wave motor control device for controlling, the remaining drive amount becomes smaller than a predetermined value from the remaining drive amount calculation means for calculating the remaining drive amount of the vibration wave motor and the output of the remaining drive amount calculation means. And a vibration switching means for switching the traveling wave vibration generated on the surface of the vibrator to the standing wave vibration according to the output of the judging means, and controlling the generation time of the standing wave vibration. There is provided a vibration wave motor control device comprising: a vibration generation time control means.

In the vibration wave motor control device according to the present invention,
If it is expected that the next drive will continue after the drive of the motor is stopped, it is possible to improve the control characteristics of the motor in the repeated start-up by keeping the oscillator of the motor in the standing wave oscillation state. Characterize.

In order to solve the above-mentioned problems, the invention of claim 2 is a vibration wave motor control for controlling a vibration wave motor comprising a vibrator for causing traveling wave vibration on the surface by an electro-mechanical energy conversion element. In the device, a remaining drive amount calculation means for calculating the remaining drive amount of the vibration wave motor, a comparison means for comparing the remaining drive amount calculated by the remaining drive amount calculation means with a predetermined value, and There is provided a vibration wave motor control device comprising: a vibration switching unit that switches a generated vibration from a traveling wave vibration to a standing wave vibration according to an output of the comparison unit.

According to the present invention, the vibration wave motor follows the drive signal with high responsiveness to the drive signal even when the drive direction is continuously or frequently switched or when restarting is repeated after a short stop. A vibration wave motor control device is provided.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

The following embodiment is a case where the present invention is applied as a control device of a vibration wave motor mounted on a lens barrel for a single lens reflex camera, but the present invention is applied to a vibration wave motor of other equipment. Of course, it can be applied.

<Embodiment> FIGS. 1 and 2 are drawings which best show the features of the present invention. FIG. 1 shows an interchangeable lens and FIG. 2 shows a camera body.

In FIG. 1, 1 is a microcomputer on the lens side, 2,
Reference numeral 3 is a photo interrupter, 2 is a moving amount of the focus lens, and 3 is a moving amount of the zoom lens.
Reference numerals 4 and 5 are vibration wave motor drive circuits, which will be described in detail with reference to FIG. 6, 7, 8 and 9 are resistors, 7 and 9 are for setting the current of the light emitting side LEDs of the photo interrupters 2 and 3,
Reference numerals 6 and 8 connect the emitter of the phototransistor on the light receiving side to the ground.

A DC / DC converter 10 boosts the battery voltage supplied from the camera to a voltage capable of driving the vibration wave motor (USM). Reference numeral 11 denotes a transistor, which functions as a control switch for supplying a voltage supplied from the camera as an IC circuit power supply to an analog circuit, and is controlled by the microcomputer 1. Reference numerals 12 and 13 denote pulse plates, and 12 denotes the movement amount of the focus drive system, that is, the rotation amount of the focus adjustment barrel 38, which is used in the photo interrupter 2 described above.
In order to detect with, a radial slit is opened in a disc-shaped plate. Reference numeral 13 is attached to the cam barrel 27 with the same structure and is used for detecting the movement amount of the variable power optical system. Reference numeral 20 denotes a lens fixing cylinder, which is connected to the camera body by a mount 43. Reference numeral 21 denotes a vibration wave motor pressing ring for magnification change, 22 is a spring for pressing the vibration wave motor, 23 is a piezoelectric element, 24 is a stator of the vibration wave motor for magnification change, 25 is a rotor of the vibration wave motor for magnification change,
26 is a felt for absorbing vibration, 27 is the above-mentioned cam cylinder,
With the cam barrel rear ball 28 and the cam barrel front ball 29,
Simultaneously with the pressurization of the vibration wave motor for zooming, the cam cylinder 27
Hold rotatably.

Reference numeral 30 is a zoom pin, and 31 is a variable magnification optical system holding cylinder. The rotation of the cam barrel 27 causes the zoom pin 30 fitted in the groove of the cam barrel to move back and forth, and the variable magnification optical system holding barrel 31 also moves forward and backward. Move.

Reference numeral 32 is a focus vibration wave motor pressing ring, 33 is a spring for pressing the vibration wave motor, 34 is a piezoelectric element, 35 is a focus vibration wave motor stator, and 36 is a focus vibration wave motor stator.
Is a rotor of the vibration wave motor for focus, 37 is a felt for absorbing vibration, 38 is a rotary cylinder for focus, and together with the focus rotary cylinder rear group ball 39 and the focus rotary cylinder front group ball 40, the focus vibration wave motor is pressed. At the same time as receiving, the focus rotation barrel 38 is rotatably held.
Reference numeral 41 is a focus pin, and 42 is a focus optical system holding barrel. The rotation of the focus rotary barrel 38 causes the focus pin 41 fitted in the groove of the focus rotary barrel to move back and forth, and the focus optical system holding barrel 42 moves back and forth accordingly. To do.

Reference numeral 43 denotes a focus brush, which is attached to the focus rotation shaft 38 and slides on a focus position encoder FENC attached on the circumference of the fixed cylinder to move the near end and the infinite end of the focus rotation cylinder. To detect. Note that F0 and F1 of the focus position encoder FENC are connected to the input ports F0 and F1 of the microcomputer 1,
OM0 is connected to the output port COM0 of the microcomputer 1.

A zoom brush 44 is attached to the cam barrel 27 and slides on a zoom encoder ZENC mounted on the circumference of the fixed barrel to detect the wide end and the tele end of the cam barrel 27 and at the same time. A zoom encoder showing a specific focal length is configured by dividing the wide end and the tele end. In addition, Z0 to Z3 of the zoom encoder ZNEC
Is connected to the input ports Z0 to Z3 of the microcomputer 1, and C
OM0 is connected to the output port COM0 of the microcomputer 1.

Numerals t01 to t07 are terminals for connecting the camera side and the lens. t01 is VD which is the power supply for IC
D supply terminal, t02 is a clock terminal for synchronizing serial communication between camera lenses, t03 is an input terminal of data to the lens side of the same serial communication, and t04 is an output terminal of data from the lens side of the same serial communication. , T05 is IC
A system ground terminal, t06 is a terminal for supplying power to a drive system such as USM, and t07 is a ground terminal for the drive system such as USM.

S1 is an auto focus / manual focus changeover switch, S2 is a close-up drive instruction switch during manual focus, S3 is an infinite direction drive instruction switch during manual focus, S4 is a wide-angle side drive instruction switch for zoom drive, and S5 is This is an infinite side drive instruction switch for zoom drive.

Next, each terminal of the lens microcomputer 1 of FIG. 1 will be described.

VDD is a power supply terminal, CLK is a clock input terminal for synchronizing serial communication between camera lenses,
SBI is a data input terminal to the lens side of the same serial communication, SBO is an output terminal of data from the lens side of the same serial communication, DGND is an IC ground terminal, CNTL
Is an output voltage ON / OFF control terminal of the DC / DC converter 10, COM0 is an output terminal corresponding to the ground level of each SW (switch), WIDE is a wide-angle side zoom drive instruction switch input terminal, and TELE is a telephoto side zoom drive instruction switch. Input terminal, FAR is an infinite direction drive instruction switch input terminal for manual focus, NEAR is a close direction drive instruction switch input terminal, A / M is an auto focus / manual focus instruction switch input terminal, F
1, F0 are focus encoder input terminals, Z3, Z
2, Z1 and Z0 are zoom encoder input terminals, PC1 is a focus pulse encoder input terminal, PC2 is a zoom pulse encoder input terminal, and a circuit USMBLK1 described later is provided.
Ain connected to the A-phase signal input terminal of the vibration wave motor described later, Sin is the drive state monitor electrode of the vibration wave motor, that is, the input terminal of the S-phase signal, A is the A-phase drive signal output terminal of the vibration wave motor, and B is B-phase signal output terminal of vibration wave motor,
Sin, Ain connected to the circuit USMBLK2 described later,
The same applies to A and B. E1ON is the transistor O
N / OFF control output terminal.

Next, referring to FIG. 2, the schematic structure of the camera will be described.

In FIG. 2, 100 is a microcomputer on the camera side, 101 is a DC / DC converter for stabilizing the voltage of the IC system of the camera body and the lens, 102, 10
Reference numeral 3 is a motor driver, 104 is a mirror-up, shutter charge and winding motor, and 105 is a rewinding motor.

Reference numeral 106 denotes a distance measuring sensor having a plurality of photoelectric conversion elements, and the sensor control circuit 107 controls storage, reading, and the like. Reference numeral 108 denotes a main mirror that reflects the light beam from the lens to the finder side. Further, a part of the central portion of the main mirror is a half mirror, and the light transmitted through the main mirror is reflected by the sub mirror 109 and guides the light flux to the distance measuring sensor. 110 is a focusing screen, 111 is a condenser lens, 11
2 is a penta prism, 113 is an eyepiece, and 114 is a photometric photoelectric conversion element.

Reference numeral 115 denotes a display element, which is a prism 116.
The light flux is bent at a right angle by the display, and is displayed below the viewfinder from the eyepiece 113 side.

A shutter 117 and a shutter drive circuit 118 control the shutter opening time by controlling the shutter front curtain drive magnet and the shutter rear curtain drive magnet. 119 is a switching element for controlling lens power supply, 120 is a battery, 121 is a camera mount,
Is.

S101 is a distance measurement start switch for photometry, S1
Reference numeral 02 is a release start switch, S103 is a lens power control switch, and when the lens mount 43 of FIG.
103 is closed, and power is supplied to the lens side.

Numerals t01 to t07 are terminals on the camera side for connecting the above-mentioned camera side and the lens.

Next, each terminal of the camera microcomputer 100 of FIG. 2 will be described.

VDD is a power supply terminal, CLK is a clock input terminal for synchronizing serial communication between camera lenses,
SBO is a data output terminal viewed from the same serial communication camera side, SBI is a data input terminal viewed from the same serial communication camera side, DGND is an IC ground terminal, and CNT.
0 is an ON / OFF control terminal of a switching element 119 for controlling the power system power supply to the lens, and CNT1 is DC /
ON / OFF control terminal of the DC converter 101, S1 is an input terminal of a photometric distance measuring start switch, S2 is an input terminal of a release switch, and MC2 and MC3 are rewinding motors 10.
5 control terminals, MC0, MC1 are hoisting motors 104
Control terminal, SIN is an input terminal of the photometric sensor 114, D
O is a display data output terminal to the display element 115, MG0 is a front curtain drive start signal output terminal of the shutter 117, MG1 is a rear curtain drive start signal output terminal of the shutter 117, Cl is a data input terminal of the photometric sensor 106, and CO is Photometric sensor 1
06 is a control signal output terminal.

Next, the circuit US in the lens microcomputer 1 of FIG.
The contents of MBLK1 and USMBLK2 will be described with reference to FIG. In the figure, 201 is a D / A converter, the input of which is connected to internal 8-bit ports P00 to P07 (not shown) of the microcomputer 1 for the lens,
Converts the digital output of it into a voltage. A voltage-frequency converter (VCO) 202 generates a frequency (32 times the driving frequency of the vibration wave motor in this embodiment) according to the output voltage of the D / A converter 201.

Reference numeral 203 is a frequency dividing circuit in which five stages of D flip-flops are connected in series, and the internal structure is shown in FIG. 20
Reference numerals 4 and 207 denote power amplifiers whose internal configuration is shown in FIG. Reference numeral 205 denotes a shift register having 15 stages, the internal configuration of which is shown in FIG. A multiplexer 206 inputs internal output ports P10 to P13 (not shown) of the lens microcomputer 1 to select inputs Q0 to Q15. 208, 2
Reference numeral 09 is a comparator, and 208 is the vibration wave motor A.
The phase signal is compared with a predetermined level, and 209 compares the S phase signal with a predetermined level. A phase detector 210 measures the phase difference between the A-phase comparator signal and the S-phase comparator signal.

An EXOR gate 211 is connected to an internal output port P14 (not shown) of the lens microcomputer 1 and sets the driving direction of the vibration wave motor. In this embodiment, the vibration wave motor rotates in the near direction with H, the wide direction with zoom, the infinite direction with L, and the telescopic direction with zoom. Reference numerals 212 and 213 denote AND gates, which are similarly connected to an output port (not shown) of the lens microcomputer 1.
When H, the vibration wave motor is driven, and when L, the vibration wave motor is stopped.

FIG. 4 is an internal configuration diagram of the above-mentioned frequency divider 203. By connecting D flip-flops in a 5-stage series, the input to the CKIN terminal is divided by 32 and output to the OUT terminal.

FIG. 5 is an internal block diagram of the shift register 205 described above, in which 15 stages of D flip-flops are connected in series in synchronization with the clock.

FIG. 6 is an internal configuration diagram of the above-mentioned power amplifier DRV. 221 and 222 are FETs, 223 is an NPN transistor, 224 is a PNP transistor, 225, and 2.
26 and 227 are resistors, 228 and 229 are protection diodes, and 230 is a matching coil.

Next, the vibration wave motor will be described with reference to FIG.

FIG. 8 is a diagram showing an arrangement state of the electrostrictive elements 23 or 34 arranged on the back surface of the stator 24 or 35 of the vibration wave motor. A and B in FIG. 8 are the first and the second arranged on the stator in the illustrated phase and polarization relationship, respectively.
The electrostrictive element group. S is an electrostrictive element for a sensor which is arranged at a position shifted in phase by 45 ° with respect to the first electrostrictive element group B. These electrostrictive elements may be individually attached to the vibrating body, or may be integrally formed by polarization treatment.

In FIG. 8, A ₁ and B ₁ represent drive electrodes for the first and second electrostrictive element groups, and a frequency voltage is applied to the electrode A and a phase different from that of the electrode B. By applying the frequency voltage, a progressive vibration wave is formed on the surface of the stator.

Further, S represents a sensor electrode for the sensor electrostrictive element S1, and when the vibration wave is formed on the surface of the stator, the sensor electrode S produces a frequency voltage in accordance with the vibration state of the vibration wave. Then, the vibration of the vibrator is detected by the sensor electrode S. The vibration wave motor has a characteristic that the phase relationship between the drive voltage to the resonance state A electrode and the output voltage from the sensor electrode has a specific relationship. Of the electrostrictive element group A and the sensor electrostrictive element S1. In the case of the present embodiment, in the forward rotation state, a resonance state is shown when the phases of the signal waveforms of the electrodes A and S deviate by 135 °, and in the reverse rotation state, a resonance state is shown when deviated by 45 °. The phase difference relationship is deviated.

FIG. 9 is a diagram showing the phase characteristics between the A phase and the S phase of the vibration wave motor. The horizontal axis represents the drive frequency f, the vertical axis represents the phase difference θ between the A phase and the S phase, and the vertical axis 2 The number of revolutions n is taken. In the figure, the phase difference is smaller toward the top,
The rotation speed n increases as it goes upward, and the frequency f increases toward the right.

As the vibration wave motor scans the drive frequency from the higher side to the lower side, the number of revolutions increases and the phase difference θ between the A phase and the S phase also decreases. However, when the frequency is further lowered below the resonance frequency f0, the rotation suddenly stops and the phase difference θ also rapidly changes. Further, this characteristic has a characteristic that it shifts to the left and right depending on temperature and load, and shifts to the right in FIG. 9 especially when the load becomes heavy.

Next, the operation of the above embodiment will be sequentially described with reference to FIG. Since the present invention relates to the drive control of the vibration wave motor, the operation of the microcomputer 1 on the lens side will be mainly described, and the operation of the microcomputer 100 on the camera side will be omitted.

FIG. 10 shows a lens initialization process. Since the encoder used in the lens of the present embodiment is a combination of an absolute encoder with rough division for zooming and focusing and an incremental encoder with fine division, fine position control is determined by the incremental encoder. However, since the incremental encoder only knows the relative position, it is necessary to perform the positioning at a predetermined timing (when the battery is replaced, the lens is attached, the power switch is turned on, etc.).

[Step 101] The zoom drive motor is driven to the end in the wide direction to set the focal length to the wide end.

[Step 102] The focusing lens is driven to the end in the infinite direction, and the focusing lens is set to the infinite end.

[Step 103] A focus pulse counter (not shown) in the lens microcomputer 1 for counting the focus drive pulses detected by the focus drive amount detecting interrupter 2 is reset.

[Step 104] A focus drive target counter (not shown) in the lens microcomputer 1 indicating the drive target position of the focusing lens is reset.

[Step 105] A zoom pulse counter (not shown) in the lens microcomputer 1 for counting the zoom drive pulses detected by the zoom drive amount detecting interrupter 3 is reset.

[Step 106] A zoom drive target counter (not shown) in the lens microcomputer 1 indicating the drive target position of the zoom lens is reset.

[Step 107] The focus motor stop timer and the zoom motor stop timer are set to the operation prohibition mode.

[Step 108] The focus drive mode and the zoom drive mode are set to stop.

[Step 109] The initialization process is terminated and control is passed to the main routine shown in FIG.

Next, the driving process during zooming in the main routine will be described with reference to FIG.

[Step 201] The processing is branched according to the setting of the zoom drive direction setting switch. That is, FIG.
Zoom switch S4 (TELE) S5 (WID
Depending on the combination of E), if TELE is on, the process branches to step 203, if WIDE is on, the process branches to step 204, and if both switches are on or off, the process branches to step 202. .

[Step 202] In the zoom stop mode, 0 is set as the zoom drive addition amount.

[Step 203] In the case of the TELE direction zoom drive, the zoom drive addition amount is set to a predetermined value + K.
In the present invention, the drive amount is + when the zoom drive is in the TELE direction, and the drive amount is − when the zoom drive is in the WIDE direction.

[Step 204] The zoom stop timer mode and the focus stop timer mode are set to enable.

[Step 205] In the case of the WIDE direction zoom drive, a predetermined value -K is set as the zoom drive addition amount.

[Step 206] The zoom stop timer mode and the focus stop timer mode are enabled.
Set to.

[Step 207] The addition amount obtained in steps 202 to 204 is added to the above-mentioned "zoom drive target counter", and the value is saved as a new "zoom drive target counter".

[Step 208] The "zoom pulse counter" indicating the current zoom position is read.

[Step 209] The "zoom drive counter" obtained in step 207 is subtracted from the "zoom pulse counter" obtained in step 208 to calculate the "zoom drive remaining amount".

[Step 210] In the lens microcomputer 1, a "focusing lens position table" indicating the focusing lens position with respect to the zoom position shown in FIG. 7 is stored.
The target position of the focusing lens is calculated using the "zoom pulse counter" obtained in step 1, that is, the current focal length as a parameter, and is stored in the "focus drive target counter".

In FIG. 7, only two types of trace curves for the focusing lens are stored, one is for infinite start and the other is for close-up start, and the intermediate position is determined by interpolating both tables.

That is, the point P in FIG. 7 is obtained from the focal length at the start of focus driving and the position of the focusing lens, and the ratio m to n of the infinite start trace curve and the closest start trace curve is calculated. Then, a target drive position of the focusing lens is calculated by interpolating between the infinite start trace curve and the closest start trace curve in m: n.

Further, in this table, in a lens having a long focal length or a lens having a large zoom ratio, it is possible to improve the accuracy of focusing tracking by storing more trace curves.

[Step 211] The "focus pulse counter" indicating the current focusing lens position is read.

[Step 212] From the “focus drive target counter” obtained in step 210 to step 208
The "focus pulse counter" obtained in step 1 is subtracted to calculate the "focus drive remaining amount".

[Step 213] The zoom drive control routine is called to control the zoom drive motor.

[Step 214] The focus drive control routine is executed to control the focus drive motor.

The above steps 201 to 214
The zoom and focus motors can be controlled by continuously performing the operation of.

Next, the control of the focus drive motor will be described with reference to FIGS.

[Step 300] In the focus drive routine, first, based on the focus drive remaining amount obtained in step 212, if the drive remaining amount is 0, step 3
If the remaining drive amount is 0, the process branches to step 20.
Branch to.

[Step 301] If the "standing wave mode" is set in accordance with the focus drive mode, go to step 302.
If "stopping", the process branches to step 303, and if "traveling wave driving", the process branches to step 309.

[Step 302] If the drive direction, that is, the remaining drive amount is> 0, the close-up drive is performed. Therefore, P14 of the microcomputer 1 is set to H, and if the remaining drive amount is <0, the endless drive is performed. , P14 to L.

Further, P13 to P10 are set so that the output of the MPX 206 is delayed in phase by 90 ° with respect to the output of the ÷ 32 frequency divider 203.

[Step 303] The same processing as in step 302 is performed even when the drive mode is "stopped".

[Step 304] In order to set the initial starting frequency fm of the vibration wave motor described with reference to FIG. 9 or a slightly higher frequency, P07 to P of the lens microcomputer 1 are set.
A predetermined value is set to 00. Since the optimum frequency to be applied to the vibration wave motor varies depending on the temperature and load, set it to the highest frequency that can be set at the first startup, and set the frequency at which the vibration wave motor can actually be driven from the next time onward. Is preferred.

[Step 305] If the DC / DC converter 10 is currently in the on mode, the process branches to step 308, and if it is the off mode, the process branches to step 306.

[Step 306] C of the lens microcomputer 1
Set the NTL terminal to L and start the DC / DC converter.

[Step 307] Since there is a delay from the start of operation of the DC / DC converter to the generation of a predetermined voltage, a predetermined waiting time is added until the start-up is completed. It is also possible to monitor the output voltage HV of the DC / DC converter and add a waiting time until it reaches a predetermined voltage.

[Step 308] The internal port P15 of the lens microcomputer 1 is set to H to start driving the vibration wave motor.

[Step 309] If the phase difference signals P23 to P20 between the A phase and the S phase detected by the phase detector 210 are read and the phase difference indicates the vicinity of the resonance frequency of the vibration wave motor, the explanation will be given with reference to FIG. As described above, there is a risk that the vibration wave motor will suddenly stop. Therefore, the process branches to step 313 in order to increase the drive frequency, and to step 310 if it is higher than the resonance frequency.

[Step 310] The drive target speed of the vibration wave motor is calculated from the current remaining drive amount. In this embodiment, a ROM (not shown) in the lens microcomputer 1 has a table, but the optimum speed may be calculated and obtained.

[Step 311] The target speed obtained in step 310 is compared with the current speed of the vibration wave motor based on the pulse interval detected by the interrupter 2, and if the speed is faster than the target speed, a step is performed to reduce the speed. If the target speed is achieved or if it is within a predetermined range near the target speed, the current state is maintained and the process returns to the main routine.

[Step 311] The drive frequency is lowered by a predetermined value and the process returns to the main routine.

[Step 313] The drive frequency is increased by a predetermined value and the process returns to the main routine.

[Step 320] The process branches from step 300 to return to the main routine if the stop timer mode is disable and branch to step 321 if enable is enabled.

[Step 321] When the drive stop timer is being activated, that is, when the vibration wave motor is waiting to be driven in the standing wave mode, the process branches to step 322, and when it is stopped, the standing wave mode is set. Branches to step 329.

[Step 322] If the drive stop timer is counting up, that is, if the standing wave drive mode after the driving is ended, the process branches to step 323 and the count is not counted up, that is, standing wave standby. If the mode is within the predetermined time, the standing wave standby mode is maintained and the process returns to the main routine.

[Step 323] Stop the drive stop timer.

[Step 324] The port P15 in the lens microcomputer 1 is set to L, and the standing wave drive of the vibration wave motor is stopped.

[Step 325] If another motor, that is, a zoom motor is being driven, the process branches to step 327.

[Step 326] When no other motor is driven, the DC / DC converter is turned off.

[Step 327] The drive stop timer mode is set to disable, and the process returns to the main routine.

[Step 329] If the drive stop timer is stopped in step 321, the drive stop timer is started to set the standing wave standby mode.

[Step 330] ÷ 32 The lens microcomputer 1 is arranged so that the output of the frequency divider 203 and the output signal of the multiplexer 206 are in phase, that is, in the standing wave drive mode.
Then, a predetermined value is set in P10 to P13 and the process returns to the main routine.

The zoom drive control can be controlled by the same method as the focus drive control, and the description thereof will be omitted.

[0109]

As described above, the standing wave mode is maintained for a predetermined time after the driving of the vibration wave motor to start the vibration wave motor when the vibration wave motor is continuously started. It has the effect of improving the characteristics.

<Second Embodiment> In the first embodiment, the standing wave drive mode is maintained for a predetermined time after the driving of the vibration wave motor is finished, and the vibration wave motor is made to stand by to drive the vibration wave motor. Although the starting characteristic is improved, in the second embodiment, in the same hardware configuration as the first embodiment,
This is an example in which the vibration wave motor is made to stand by in the standing wave mode when it is expected that the vibration wave motor is continuously driven while the zoom operation switch is being pushed.

FIG. 14 shows the same lens initialization process as in FIG.

[Step 401] The zoom drive motor is driven in the wide direction to the end to set the focal length to the wide end.

[Step 402] The focusing lens is driven in the infinite direction to the end, and the focusing lens is set to the infinite end.

[Step 403] A focus pulse counter (not shown) in the lens microcomputer 1 for counting the focus drive pulses detected by the focus drive amount detecting interrupter 2 is reset.

[Step 404] A focus drive target counter (not shown) in the lens microcomputer 1 indicating the drive target position of the focusing lens is reset.

[Step 405] A zoom pulse counter (not shown) in the lens microcomputer 1 for counting the zoom drive pulses detected by the zoom drive amount detecting interrupter 3 is reset.

[Step 406] A zoom drive target counter (not shown) in the lens microcomputer 1 indicating the drive target position of the zoom lens is reset.

[Step 407] The focus motor stop timer and the zoom motor stop timer are set to the operation prohibition mode.

[Step 408] The initialization processing is terminated and the control is transferred to the main routine shown in FIG.

Next, the drive processing during zooming in the main routine will be described with reference to FIG.

[Step 501] The processing is branched according to the setting of the zoom drive direction setting switch. That is, FIG.
Zoom switch S4 (TELE) S5 (WID
Depending on the combination of E), if TELE is on, the process branches to step 503, if WIDE is on, the process branches to step 504, and if both switches are on or off, the process branches to step 502. .

[Step 502] In the zoom stop mode, 0 is set as the zoom drive addition amount.

[Step 503] In the TELE direction zoom drive, the zoom drive addition amount is set to a predetermined value + K.
In the present invention, the drive amount is + when the zoom drive is in the TELE direction, and the drive amount is − when the zoom drive is in the WIDE direction.

[Step 505] In the case of WIDE direction zoom drive, a predetermined value -K is set as the zoom drive addition amount.

[Step 507] The addition amount obtained in steps 502 to 204 is added to the above-mentioned "zoom drive target counter", and the value is stored as a new "zoom drive target counter".

[Step 508] The "zoom pulse counter" indicating the current zoom position is read.

[Step 509] The "zoom drive counter" calculated in step 507 is subtracted from the "zoom drive target counter" calculated in step 507 to calculate the "zoom drive remaining amount".

[Step 510] In the lens microcomputer 1, a "focusing lens position table" indicating the focusing lens position with respect to the zoom position shown in FIG. 7 is stored. From the table, step 508 is stored.
The target position of the focusing lens is obtained by using the "zoom pulse counter" obtained in step 1, that is, the current focal length as a parameter, and is held in the "focus drive target counter".
The first method for calculating the target position of the focusing lens is
Since it has been described in the embodiment, the description thereof will be omitted.

[Step 511] The "focus pulse counter" indicating the current focusing lens position is read.

[Step 512] From the “focus drive target counter” obtained in step 510 to step 508
The "focus pulse counter" obtained in step 1 is subtracted to calculate the "focus drive remaining amount."

[Step 513] The zoom drive control routine is called to control the zoom drive motor.

[Step 514] The focus drive control routine is called to control the focus drive motor.

The above steps 501 to 514
The zoom and focus motors can be controlled by continuously performing the operation of.

Next, the control of the focus drive motor will be described with reference to FIGS. 16 and 17.

[Step 600] In the focus drive routine, first, based on the focus drive remaining amount obtained in step 512, if the drive remaining amount is 0, step 6
If the remaining drive amount is not 0, the process branches to step 20. Step 601
Branch to.

[Step 601] If the "standing wave mode" is set in accordance with the focus drive mode, go to step 602.
If "stopping", the process branches to step 603. If "traveling wave driving", the process branches to step 609.

[Step 602] If the drive direction, that is, the remaining drive amount is> 0, the drive is in the close-up direction. Therefore, P14 of the microcomputer 1 is set to H. If the remaining drive amount is <0, the drive is infinite. , P14 to L.

Further, P13 to P10 are set so that the output of the MPX 206 is delayed in phase by 90 ° with respect to the output of the frequency divider 203.

[Step 603] The same processing as in step 602 is performed even when the drive mode is "stopped".

[Step 604] In order to set the initial starting frequency fm of the vibration wave motor described with reference to FIG. 9 or a slightly higher frequency, P07 to P of the lens microcomputer 1 are set.
A predetermined value is set to 00. Since the optimum frequency to be applied to the vibration wave motor varies depending on the temperature and load, set it to the highest frequency that can be set at the first startup, and set the frequency at which the vibration wave motor can actually be driven from the next time onward. Is preferred.

[Step 605] If the DC / DC converter 10 is currently in the on mode, the process branches to step 608, and if it is the off mode, the process branches to step 606.

[Step 606] C of the lens microcomputer 1
Set the NTL terminal to L and start the DC / DC converter.

[Step 607] Since there is a delay from the start of operation of the DC / DC converter to the generation of a predetermined voltage, a predetermined waiting time is added until the start-up is completed. It is also possible to monitor the output voltage HV of the DC / DC converter and add a waiting time until it reaches a predetermined voltage.

[Step 608] The internal port P15 of the lens microcomputer 1 is set to H to start driving the vibration wave motor.

[Step 609] Phase difference signals P23 to P20 between A phase and S phase detected by the phase detector 210.
If the phase difference indicates the vicinity of the resonance frequency of the vibration wave motor, there is a risk that the vibration wave motor will suddenly stop as described with reference to FIG. 9, so the process branches to step 613 in order to increase the drive frequency. If the stable state is higher than the resonance frequency, the process branches to step 610.

[Step 610] From the current remaining drive amount,
The drive target speed of the vibration wave motor is calculated. In this embodiment, a ROM (not shown) in the lens microcomputer 1 has a table, but the optimum speed may be calculated and obtained.

[Step 611] The target speed obtained in step 610 is compared with the current speed of the vibration wave motor based on the pulse interval detected by the interrupter 2, and if the speed is faster than the target speed, a step is executed to decelerate. If the target speed is achieved or if it is within a predetermined range near the target speed, the current state is maintained and the process returns to the main routine.

[Step 612] The drive frequency is lowered by a predetermined value and the process returns to the main routine.

[Step 613] The drive frequency is increased by a predetermined value and the process returns to the main routine.

[Step 620] The flow branches from step 600 to step 622 when the zoom SW is pressed even though the remaining drive amount is 0, and to step 621 when the zoom SW is not pressed.

[Step 621] The port P15 in the lens microcomputer 1 is set to L, and the standing wave drive of the vibration wave motor is stopped.

[Step 622] / Lens microcomputer 1 so that the output of the frequency divider 203 and the output signal of the multiplexer 206 are in phase, that is, the standing wave drive mode is set.
A predetermined value is set to P10 to P13.

[Step 623] If another motor, that is, the zoom motor is being driven, the process branches to step 627.

[Step 624] If no other motor is driven, the DC / DC converter is turned off.

[Step 625] Return to the main routine.

Since the zoom drive control can be controlled in the same manner as the focus drive control, the description thereof will be omitted. Further, in the second embodiment, the following describes the follow-up operation of the focus lens during zooming. For example, in the operation of the camera for auto-focusing, the focus mode follows the continuous mode, that is, while the shutter button is pressed. Even when the focus vibration wave motor is not driven when focusing is continued when the camera is in focus, the vibration wave motor is kept in the standing wave mode while the camera is ready to take a picture. it can.

[0157]

As described above, in the second embodiment, when the drive of the vibration wave motor is continuously generated, the standing wave mode is maintained even if the drive of the vibration wave motor is unnecessary. This has the effect of improving the tracking characteristics of the vibration wave motor.

<Correspondence between Invention and Embodiment> Claims 1 and 2
"Remaining drive amount calculation means", "discrimination means",
The "comparison means", "vibration switching means", and "vibration generation time control means" are provided in the lens microcomputer 1 including the vibration wave motor control circuits USMBLK1 and USMBLK2 described in the first and second embodiments. The general functions of the above are shown in the flow charts of FIGS. 12 and 13 and FIGS.

[0159]

According to the first aspect of the present invention, the standing wave vibration is continuously generated in the vibrator of the vibration wave motor for a predetermined time after the driving of the vibration wave motor is started, thereby continuously starting the motor. It is possible to improve the start-up characteristic in the case of making it.

According to the second aspect of the present invention, when the driving direction of the motor is continuously reversed, a standing wave vibration is generated in the vibrator of the motor even if the restart of the motor is unnecessary. By continuing to generate, the tracking characteristic of the motor can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a lens barrel equipped with a vibration wave motor control device of the present invention.

FIG. 2 is a diagram showing a configuration of a camera body mounted on the lens barrel.

FIG. 3 is a vibration wave motor drive circuit USMBL shown in FIG.
K1, USMBLK2 and USMDRV1, USMDR
The schematic diagram showing the contents of V2.

4 is a diagram showing a configuration of a frequency divider circuit 203 shown in FIG.

5 is a diagram showing a configuration of a shift register 205 shown in FIG.

6 is a diagram showing the contents of power amplification circuits 204 and 207 shown in FIG.

FIG. 7 is a diagram showing a correspondence between a starting characteristic of the vibration wave motor and an actual movement position of the lens in a camera using the vibration wave motor as a drive source of a focus lens and a zoom lens.

FIG. 8 is a diagram showing an electrode arrangement of a piezoelectric element attached to a vibrator of a vibration wave motor.

FIG. 9 is a vibration wave motor drive characteristic diagram showing the relationship between the frequency and phase difference of the drive signal applied to the vibrator of the vibration wave motor and the rotation speed of the motor.

FIG. 10 is a flowchart of an initial operation of a control circuit of a camera equipped with the vibration wave motor control device according to the first embodiment of the present invention.

11 is a diagram showing a main routine following the operation of FIG.

FIG. 12 is a flowchart showing a control operation for the vibration wave motor (focus motor).

FIG. 13 is a flowchart showing a control operation before and after stopping the vibration wave motor.

FIG. 14 is a flowchart of an initial operation of a control circuit of a camera equipped with the vibration wave motor control device according to the second embodiment of the present invention.

15 is a diagram showing a main routine following the operation of FIG.

FIG. 16 is a flowchart of drive control of a focusing vibration wave motor.

FIG. 17 is a flowchart of a control operation before and after stopping the vibration wave motor.

[Explanation of symbols]

1 ... Lens microcomputer 100 ... Camera microcomputer 2, 3 ... Interrupter 10, 101 ... D
C / DC converters 12, 13 ... Pulse plates 4, 5 ... Vibration wave motor drive circuit 6-9 ... Resistor 11 ... Transistor 20 ... Lens fixing cylinder 21 ... Magnification-changing vibration wave motor pressure ring 22 ... Disc spring 23 ... Piezoelectric Element 24 ... Stator 25 ... Rotor 26 ... Felt 27 ... Cam tube 28, 29 ... Ball 30 ... Zoom pin 31 ... Zoom optical system holding tube 32 ... Pressure ring 33 ... Disc spring 34 ... Piezoelectric element 35 ... Stator 36 ... Rotor 37 ... felt 38 ... focus rotation cylinder 39, 40 ... ball 41 ... focus pin 42 ... focus optical system holding cylinder 43 ... focus brush 44 ... zoom brush 102, 103 ...
Motor driver 104, 105 ... Motor 106 ... Distance measuring sensor 107 ... Sensor control circuit 108 ... Main mirror 109 ... Sub mirror 110 ... Focusing screen 111 ... Condenser lens 112 ... Penta prism 113 ... Eyepiece 114 ... Photometric photoelectric conversion element 115 ... Display Element 116 ... Prism 117 ... Shutter 118 ... Shutter drive circuit 119 ... Lens power control switching element 120 ... Battery

Claims (2)

[Claims] 1. A vibration wave motor control device for controlling a vibration wave motor comprising a vibrator which causes traveling wave vibration on a surface by an electro-mechanical energy conversion element, wherein a remaining drive amount of the vibration wave motor is controlled. Remaining drive amount calculating means for calculating, determining means for determining from the output of the remaining drive amount calculating means that the remaining drive amount has become smaller than a predetermined value, and traveling wave vibration generated on the surface of the vibrator. A vibration wave motor comprising: a vibration switching means for switching to standing wave vibration according to the output of the discrimination means; and a vibration generation time control means for controlling the generation time of the standing wave vibration. Control device. 2. A vibration wave motor control device for controlling a vibration wave motor comprising a vibrator for causing traveling wave vibration on a surface by an electro-mechanical energy conversion element, wherein a remaining drive amount of the vibration wave motor is controlled. Remaining drive amount calculating means for calculating, comparing means for comparing the remaining drive amount calculated by the remaining drive amount calculating means with a predetermined value, and vibration generated on the surface of the vibrator according to the output of the comparing means. A vibration wave motor control device comprising: a vibration switching unit that switches from traveling wave vibration to standing wave vibration.