JPH03183399A - Pulse motor drive device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a driving device for a pulse motor used in an autofocus device of a video camera and the like.

[Conventional technology]

In the autofocus device of a video camera.

One conventional method of driving a focusing lens using a pulse motor (including a stepping motor) is described, for example, in Japanese Patent Laid-Open No. 59-66274''+. ■ Position) is defined by providing a mechanical stopper, and by supplying a certain number of pulses to the pulse motor to send the focusing lens in the direction of , the focusing lens is forcefully pressed against the stopper and the position is determined. This is for matching.

In the following, forcibly pressing the focusing lens against the stopper in this manner will be referred to as oc rubbing.

If only one positional shift occurs, and the position of the focusing lens (hereinafter referred to as lens position) is near the α position, C rubbing is forcibly performed to initialize the lens position. Therefore, even if a step out (misstep) occurs in the pulse motor during operation, the lens position is brought to the vicinity of the α position and the above-mentioned initialization is performed, and the step out is corrected.

[Problem to be solved by the invention]

As described above, in the above-mentioned conventional technology, positioning and step-out correction can be performed with a simple configuration, but the following points are not taken into consideration, resulting in the rjj problem.

(1) Problem with C positioning by OC rubbing 2 When the power is turned on, C positioning by rubbing is performed.

At this time, the supporting body of the focusing lens is strongly pressed against the stopper, so the stress is large, and there is a risk that the movement screw part may become stuck due to positional displacement force. , a loud collision sound will occur.

(2) Problem due to blurring during focusing operation (2) There is a possibility that the pulse motor may lose synchronization during focusing operation, so in order to correct this, α rubbing is performed as described above. This ctg attachment is performed when the lens position is near the α position, but this operation is unrelated to the focusing operation and is an unnecessary operation during shooting, so it may not be noticed by the user. It may also be considered a malfunction.

In addition, the above problem (1) also occurs at the same time, and in particular, collision noise is generated during the focusing operation, which is a very bothersome problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pulse motor drive device that solves these problems and makes it possible to correct synchronization without relying on J-mounting.

[Means to solve the problem]

In order to achieve the above object, the present invention provides step-out detection means for detecting step-out of the pulse motor using detection pulses from a rotation detector of the pulse motor.

Further, the present invention provides means for generating a step-out correction signal at the timing of generation of the first detection pulse after the step-out detection means detects the step-out.

Furthermore, the present invention predicts the generation timing of the detection pulse from the active pulse of the pulse motor and generates the predicted rotation detection pulse at this generation timing, but the step-out correction (the predicted rotation occurring before and after the A first rotation amount of the pulse motor between the detection pulse and an expected rotation detection pulse that precedes the detection pulse, and a first rotation amount that is expected to be generated following the detection pulse. means for calculating the second rotation amount of the pulse motor between the p-core rotation detection pulse and the second rotation amount of the pulse motor, comparing the magnitudes thereof, and shifting the generation timing of the expected rotation detection pulse according to the smaller rotation amount; will be established.

[Effect]

The detection pulse of the rotation detector is generated in synchronization with the rotation of the pulse motor. Therefore, if a step-out occurs in which the rotation of the pulse motor becomes abnormal with respect to the supplied drive pulse, a shift occurs in the timing of generation of the detection pulse based on this drive pulse. The step-out detection means detects step-out of the pulse motor by detecting a shift in the timing of generation of the detection pulse. Thereby, no matter what rotation amount the pulse motor is in, if there is a step-out, it will be detected.

Correction of synchronization is performed based on the first detection pulse generated when synchronization is detected.

For this reason, when a step-out is detected, a step-out correction signal is created in synchronization with the first subsequent detection pulse.
The amount of rotation of the pulse motor between this step-out correction signal and the expected rotation detection pulse closest thereto is calculated, and the generation timing of the expected rotation detection pulse is shifted by an amount corresponding to this amount of rotation.

The amount of rotation of the pulse motor is detected using its drive pulses. Therefore, when step-out occurs, an error occurs in detecting the amount of rotation. In this invention, the detection result of the rotation amount by this drive pulse is constantly corrected by the predicted rotation detection pulse, and even if the predicted rotation detection pulse is affected by step-out, this is corrected as described above. In addition, the amount of rotation of the pulse motor is always accurately detected. Moreover, when a step-out is detected without any overlapping and with the pulse motor rotating at an arbitrary amount, correction is performed immediately.

Therefore, the effect of the present invention is not to mechanically prevent step-out, but to correct it when step-out occurs.
Rather than a precision feed mechanism that cannot tolerate step-out during machining, it is better to be able to accurately control the position as a whole even if a portion of the step-out occurs, such as when moving an autofocus lens, which will be discussed later. It has an action suitable for a feeding mechanism that is sufficient if the

〔Example〕

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

FIG. 1 is a block diagram showing an embodiment of a pulse motor drive device according to the present invention, in which 1 is a control circuit, 2 is a pulse motor, 3 is a detector, 4 is a drive circuit, and 5 is an input device. .

In the figure, a control signal is supplied from a control circuit 1 to a drive circuit 4, and the drive circuit 4 rotates the pulse motor 2 by an amount of rotation corresponding to the control signal.

The amount of rotation of the pulse motor 2 is detected by a detector 3, and the detection result is supplied to the control circuit 1.

The C positioning of the focusing lens (not shown) is performed as follows. That is, when the power is turned on or a reset operation is performed, the pulse motor 2 is rotationally driven by a control signal from the control circuit 1, and the control circuit 1 detects the origin of rotation of the pulse motor 2 based on the detection output of the detector 3. . Thereafter, the control circuit 1 rotates the pulse motor 2 by an amount of rotation corresponding to the input value from the input device 5. By appropriately adjusting this input value, the ■ position is set.

Next, the step-out correction of the pulse motor 2 is performed as follows. That is, the control circuit 1 detects step-out of the pulse motor 2 from the sending position information of the control signal sent to the drive circuit 4 and the actual position information obtained from the detection output of the detector 3, and adjusts the output timing of this detector. As the correction timing, the feed position information on the control circuit is corrected.

As described above, nv′ using a mechanical stopper C positioning and step-out correction are performed without any trouble.

This embodiment will be described in more detail below using an autofocus device for a video camera as an example.

In the autofocus device, a focusing lens is driven by a lens moving mechanism driven by a pulse motor 2. Since this embodiment can also use a conventional lens moving mechanism, a conventional example thereof will be explained with reference to FIG. However, in the same figure, 2.21 is a feed screw part, 22 is a table, 31.32 is a detector, 33 is a slit plate 33A is a slit, and parts corresponding to those in FIG. 1 are given the same reference numerals. There is.

A feed screw portion 21 is integrated with the rotating shaft of the pulse motor 2, and a table 22 provided with a focusing lens (not shown) is screwed into the feed screw portion 21. When the pulse motor 2 rotates and the feed screw portion 21 rotates, the table 22 moves in the longitudinal direction of the feed screw portion 21, thereby changing the lens position.

Further, the rotation shaft of the pulse motor 2 has a slit disk 33 provided with a slit 33A as shown in FIG. 2(b).
are integrally attached, and a detector 31 for detecting the slit 33A is fixedly provided opposite to this slit disk 33. Furthermore, a detector 3 that detects the table 22
2 is also provided. These detectors 31, 32 correspond to the detector 3 in FIG.

Now, for convenience of explanation, an active pulse P1 as shown in FIG. 3(a) is supplied to the pulse motor 2, and the pulse motor 2
rotates 1 step for every 1 translation pulse, and rotates 1 step in 5 steps.
Assuming that the detector 31 rotates, the slit disk 33
Since the slit 33A is detected every rotation of the
As shown in b), the detection pulse P2 of the detector 31 is generated every five cycles of the drive pulse PL (FIG. 3(a)). Here, this detection pulse P2 is “H” (high level)
shall be.

On the other hand, when the table 22 is in the position shown in FIG. 2(a), the detector 32 does not detect the table 22, and its detection output P3 is "L" (low level). Now, assuming that the pulse motor 2 rotates and the table 22 moves in the direction of arrow g, the detection output P3 of the detector 32 will be as follows: When the table 22 reaches the position of the detector 32 and the detector 32 detects the table 22, , +1 as shown in Figure 3(C)
Inverted from L II to “H”. The direction in which such time elapses in FIG. 3 is indicated by an arrow g.

Furthermore, if the table 22 is at the detection position of the detector 32 and moves in the direction of the arrow f, the direction of time in FIG. 3 is in the direction of the arrow f, and the detection output P3 of the detector 32 is
is reversed from "H" to LL L II as the table 22 moves away from the position of the detector 32.

FIG. 3(d) shows the detection outputs P2. of the detectors 31 and 32. P3
represents the output P4 of the AND gate whose input is
This is the detection pulse P2 that is first output from the detector 31 after being detected at , and is the last output from the detector 31 when the table 22 moving in the direction of arrow f is being detected by the detector 32. This is the detection pulse P2.

In addition, as a step feeding method of the pulse motor 2, as is well known, there are excitation methods such as 1-phase, 2-phase, or 1-2 phase excitation, but in this embodiment, any of the excitation methods is used. In short, it is sufficient to operate at the timing shown in FIG.

By the way, the detection output P3 of the detector 32 (FIG. 3(C))
Generally, it is difficult to obtain accurate reproducibility in the stroke (i.e., this edge timing and table 2
There is not necessarily a one-to-one correspondence with position 2). Therefore, the rotation amount of the pulse motor 2 and the detection output P of the detector 32
There is not necessarily a one-to-one correspondence with the edge timing of 3. On the other hand, there is an exact one-to-one correspondence between the generation timing of the detection pulse P2 of the detector 31 and the amount of rotation of the pulse motor 2, and therefore the pulse when the pulse P in FIG. 3(d) is generated. The amount of rotation of the motor 2 is constant. Therefore, by using this pulse P, a fixed origin of rotation of the pulse motor 2 can be detected.

The origin detection method itself is publicly known, and co-authored by Daiki Ebihara and one other person, "Stepping Motor Utilization Technology", 3rd edition, December 1985.
Published by Kogyo Kenkyukai Co., Ltd., pp. 228-229 on May 10th. That is, the table 22 is moved in the direction of arrow g from the state shown in FIG. 2(a), and after the detection output P3 of the detector 32 (FIG. 3(C)) becomes td HII, the first Detection pulse P (Fig. 3(d)
) is output, and the amount of rotation of the pulse motor 2 represents the origin position. By using this origin position as a reference point and counting the step feeds of the pulse motor 2, the position of the tape 22 can be detected accurately.

FIG. 4 is a block diagram more specifically showing the embodiment of FIG. 1 equipped with the lens feeding mechanism shown in FIG. 2, in which 6 is a focus control circuit, 7 is a lens position control circuit, and 8 is a ■Adjustment switch, 9 is the power supply.

10 is ■Adjuster, 11 is focusing lens.

12 is a sensor, and parts corresponding to those in the previous drawings are given the same reference numerals.

In the figure, a lens position control circuit 7 corresponds to the control circuit 1 in FIG. o:
The regulator 10 corresponds to the input device 5 in FIG. Further, the sensor 12 is an image sensor or the like.

During the focusing operation, a focus adjustment signal is supplied from the focus control circuit 6 to the lens position control circuit 7 in accordance with the deviation between the lens position of the focusing lens 1 and the in-focus position detected by means not shown. Accordingly, the lens position control circuit 7 controls the moving circuit 4, rotates the pulse motor 2, and moves the table 22 so that the lens position becomes the in-focus position.

Next, the operation for positioning the cathedral will be explained using FIG. 5.

This operation is started by turning on a power switch (not shown) or operating a reset switch (not shown).

First, origin detection is performed using the outputs of the detectors 31 and 32 (step 5o1). Next, the lens position control circuit 7 receives a voltage (hereinafter referred to as
(referred to as a set value) (step 502), and rotates the pulse motor 2 to move the focusing lens 11 to a position corresponding to this set value (step 5o3).
). In this case, ■When the adjustment switch 8 is on (step 504), the operations of steps 502 and 503 are repeated, and ■When the adjuster 10 is adjusted to change the setting value, the lens position control circuit 7 is activated by the pulse motor 2. to move the focusing lens 11 to a position corresponding to the new set value.

Positioning can be done in this way, and once this is completed,
By turning off the adjustment switch 8, the setting value of the adjuster 10 at this time is held in the lens position control circuit 7.
The subsequent C position will be defined by this held setting value. Of course, if the adjustment switch 8 is left off, the position corresponding to the value of the regulator 10 will be set to the infinite position. In this way, (1) non-contact positioning is possible without using rubbing. When this infinite positioning is completed, the position 7., k becomes the reference position for subsequent control.

Therefore, if the lens position is set to, for example, O at this point, and then the value of this lens position is changed in accordance with the drive of the pulse motor, the lens position based on the infinity position can always be determined.

FIG. 6 shows the origin detection operation in step 501 in FIG. However, it is assumed that the pulse motor 2 rotates upward in N steps.

Referring to FIG. 3, first, as shown in FIG.
2 to detect the table 22, and reset the step number i of the pulse motor 2 to zero (step 60).
1). At this time, the detection output of the detector 32 is "H71. Next, it is determined whether i=N or not (step 602).
At this time, since i=O, the process proceeds to step 603.

In this step 603, it is determined whether the pulse P4 of FIG. 3(d), which is the AND output of the detectors 31 and 32, has been obtained. If this pulse P4 has not been obtained, the number of steps i is set to 1 (=O+1). Step 605),
The pulse motor 2 is rotated by l steps to move the table 22 in the f direction (step 606). Then, the process returns to step 602 again.

In this way, the pulse motor 2 rotates by l steps to move the table 22 in the direction of the arrow f, but since the detector 31 always generates a pulse P2 once while the pulse motor 2 rotates upward, the pulse The timing at which P4 occurs is before the pulse motor 2 takes N steps. Pulse P
4 is detected (step 603), pulse motor 2
The step number i is reset to zero (step 604).
The pulse motor 2 further rotates the aesthetic knob in a direction in which the table 22 is moved in the direction of arrow f, and the process returns to step 602.

In this way, as long as the detector 32 detects the table 22, a pulse P4 is generated and the steps 602→step 603→step 604 or 605→step 6
The process 06 is repeated, and the pulse motor 2 continues to rotate so that the table 22 moves in the direction of arrow f.

In this way, when the last pulse P of the pulses P4 in FIG. 3(d) is detected, the step number i of the pulse motor 2 is reset to zero (step 604), and furthermore, the pulse motor 2 is Although it continues to rotate, the detector 32 no longer detects the table 22, so the pulse P4 is no longer generated. For this, steps 602→603
→605→606 are repeated, and the number of steps i of the pulse motor 2 reaches N.

If this is determined in step 602, the pulse motor 2
In step 607, the aesthetic knob is rotated one by one so that the table 22 moves in the g direction, and the detection output P of the detector 32 is
3 becomes it HI+ and pulse P4 is first detected (step 608).

Pulse motor 2 stops.

This first detected pulse P4 is the pulse P in FIG. 3(d), and this means that the origin is detected by the detector of the pulse motor 2.

From now on, as mentioned above, if the output of the infinity adjuster 10 is taken into the lens position control circuit 7 and the table 22 is moved according to the output value, and that position is used as the reference point of the lens 11, the so-called Infinity adjustment (back focus adjustment) of the lens can be easily performed.

Each of the operations described above is performed by using a control circuit composed of a microcomputer, for example, a cc adjustment m
This can be easily implemented by converting the output of 1o into A/DL digitization and importing it. Furthermore, with this configuration, the input device 5 may be any device that generates a set value as a digital value.

FIG. 7 is a block diagram showing a specific example of the step-out detection section of the pulse motor 2 in FIG. 1, and 13 is a setting circuit;
14 is an expected rotation detection circuit, 15 is a rotation detection circuit, 16 is a comparison circuit, and 17 is an output terminal, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, the rotation detection circuit 5 generates a detection pulse P2 shown in FIG. 3(b) in response to the detection result of the detector 31 in FIG. On the other hand, the active pulse P1 supplied to the pulse motor 2 corresponds to the rotation amount of the pulse motor 2,
Since this amount of rotation corresponds to the timing of generation of the detection pulse P2, the timing of generation of the detection pulse P2 output from the rotation detection circuit 5 can be predicted. The setting circuit 13 holds data indicating these correspondence relationships, and based on this data, the expected rotation detection circuit 4
forms an expected rotation detection pulse P2' from the drive pulse P1 and outputs it.

When the pulse motor 2 operates normally, as shown in FIG. 8, the expected rotation detection pulse P2' output from the expected rotation detection circuit 4 and the detection pulse P2 output from the rotation detection circuit 15 are the same. The waveforms have the same period and phase. The expected rotation detection pulse P2' and the detection pulse P2 are compared in phase by the comparison circuit 16, but at this time, there is no signal output from the comparison circuit 16.

However, in FIG. 8, if the pulse motor 2 loses its synchronization at the point indicated by the arrow, the phase of the detection pulse P2 is delayed and a phase difference occurs between this and the expected rotation detection pulse P2'. At this time, the comparator circuit 16 outputs a step-out detection signal E representing this phase difference.

Note that the comparison circuit ↓6 in this case can be configured with an ExOR (exclusive OR) circuit.

Furthermore, even if the detection pulse P2 advances due to step-out, the step-out detection signal E is generated in the same way.

Next, the synchronization correction operation of this embodiment will be explained with reference to FIGS. 9 to J-1. Note that here, the amount of rotation of the pulse motor 2, and therefore the position of the table 22, is detected by counting the drive pulses of the pulse motor 2 at the time of detecting the origin described above or after the α position adjustment approximately 7. This value will be defined as the lens position.

Also, since the detection pulse P2 of the detector 31 is always obtained when the origin is detected, the detection pulse P2 at this time is compared with the rotation angle of the pulse motor 2, and the resulting data is sent to the setting circuit 13 of FIG. This data is read out as the pulse motor 2 is driven, and the timing of the predicted rotation detection pulse P2' formed by the predicted rotation detection @path 14 is set.

First, FIG. 9 shows the operation when the rotational phase of the pulse motor 2 is delayed due to step-out, and the detection pulse P2 from the detector 31 is delayed. This is similar to Figure 8.

In FIG. 9, when the step-out detection signal E is output from the output terminal 17 in FIG. 7 due to the step-out of the pulse motor 2, the latch circuit is latched at the first rising edge (time tx) of the step-out detection signal E, and the LL HII signal is output. A latch output P5 is obtained. and,
This latch output P5 and detection pulse P2 are input to an AND gate to obtain an AND gate output P6. Then, a position correction signal P7 having a constant pulse width is generated from the rising edge (time tz) of this AND gate output P6, and the latch circuit is reset at the falling edge of this position correction signal P7 (time t3). Therefore, if the latch circuit is not reset, the latch output P5 will continue to be in the "H" state as shown by the broken line, but by resetting the latch circuit, the latch output P5 will remain at the "H" state until 1 time t.

Then, II L II is established, and the above AND gate is turned off.

Here, the step-out correction is the detection pulse P immediately after the step-out occurs.
2 is generated (time t2), that is, the AND gate output P6 is generated. This correction is performed by the setting circuit 13 (Fig. 7) according to the phase fluctuation of the detection pulse P2.
The data stored in the pulse motor 2 is corrected to match the phase of the expected rotation detection pulse P2' with the phase of the detection pulse P2, and the relationship between this data and the rotation amount of the pulse motor 2 is reset. At the same time, the lens position is also corrected.

For this purpose, first, when the AND gate output P6 is obtained, this generation time t2 and the expected rotation detection pulse P immediately before it are
The number of cycles (hereinafter referred to as the number of steps) ΔS of the drive pulse P1 between the generation time t1 of 2' (pulse indicated by (Q)), and the generation time t2 of the AND gate output P6 and the pulse (Q). Next expected rotation detection pulse P2' ((m)
81! The number of steps .DELTA.Sm between the occurrence time t and the time of I is detected, the magnitudes of these are compared, and the smaller one is adopted. Then, if the number of steps ΔS is small, the setting circuit 1 sets the generation timing of the expected rotation detection pulse P2' to be delayed by the number of steps ΔS.
Correct the data stored in 3. Furthermore, when the number of steps ΔSm is small, the expected rotation detection pulse P2'
so that the timing of occurrence advances by the number of steps ΔS/,
Correct the above data.

As a result, the expected rotation detection pulse P2' is
), after the data is corrected, the phase matches that of the detection pulse P2, and it correctly corresponds to the actual rotation angle of the pulse motor 2. As mentioned above, the rotation amount of the pulse motor 2, that is, the lens position, is detected by counting the drive pulses P1, so if a step-out occurs in the pulse motor 2, even if the drive pulses are actually being supplied. Regardless, the pulse motor 2 stops rotating for a moment, and the count value of the drive pulse PL changes to the pulse motor 2.
However, by regulating this count value using the corrected data as described below, this count value always correctly represents the rotation amount of the pulse motor 2.

The basic regulation method is that the detection pulse P2 indicates the true lens position regardless of the presence or absence of step-out, and the value indicating the lens position obtained by pulse counting etc. will be incorrect if the step-out detection signal E is generated. It is intended to be corrected as appropriate.

That is, at the time when the position correction confidence check P7 occurs, the expected rotation detection pulse P2 is the smaller of the step number ΔS and ΔSm.
This is corrected by setting the value of the lens position at the position (Q) in FIG. 9, where the error occurs, to a value indicating the lens position as the true lens position.

The above processing allows the correct position of the focusing lens 11 to be detected at all times.

In addition, when the detector 31 outputs one detection pulse P2 for each rotation of the pulse motor 2, and assuming that the pulse motor 2 rotates once in 40 steps, the above correction ability is possible up to 20 pulses. be. However, since the step-out is usually several pulses per rotation, it can be sufficiently corrected.

In addition, as shown in Fig. 4, a focusing lens]
, 1 by the pulse motor 2, correct lens movement during zooming is performed only after the correct position of the focus lens 11 is known. In the conventional technology described above, the correction for detecting the correct position of the focusing lens 11 is only performed near the C position, and if step-out occurs at any other position, the focusing lens feed error is accumulated. However, in this example,
Since focusing is performed regardless of the position of the focusing lens 11, 1/lens feeding can always be performed without error.

Furthermore, in the above correction operation, the correct amount of rotation of the pulse motor 2 cannot be detected until the expected rotation detection pulse P2' is corrected and the drive pulse count value is corrected after the step-out occurs. However, this is only temporary and does not pose a particular problem.

FIG. 10 shows a correction operation when the detection pulse P2 advances beyond the expected rotation detection pulse P2' due to step-out.

In this case, the first rising edge of the step-out detection signal E coincides with the rising edge (time ts) of the first detection pulse P2 after the step-out. Therefore, as in the case of FIG. 9, the AND gate output P6 is the detection pulse P2 generated at this time t5, and with this as a reference, the step-out correction is performed in the same manner as in the case of FIG.

Figure 1↓ shows detection pulse P2 and expected rotation detection pulse P2'
The pulse width is wide, and some parts overlap due to step-out.
The following describes the operation when a shift occurs in these phases.

In this case as well, the first rising edge of the out-of-step detection signal E obtained at the output terminal 17 in FIG. , a latch output P5 starting from this rising edge is obtained, and the rising edge of the AND gate output P6 coincides with the rising edge of the detection pulse P2.

Therefore, the same synchronization correction as shown in FIGS. 9 and 10 is possible.

In the case of the operation shown in FIG. 11, for example, when detecting the origin, the pulse motor 2 is operated for one rotation, and the detection pulse P2 output from the detector 31 at that time and the rotation amount of the pulse motor 2 are Setting circuit 1
3 (FIG. 7). As mentioned above, the actual circuit is implemented by software on a microcomputer or connections on a logic array, but there is no problem in realizing the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, step-out of a pulse motor can be detected with a simple circuit configuration, position error of the pulse motor due to step-out can be corrected, and pulse motor with less error can be detected. Motor feed control becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a pulse motor step-out correction device according to the present invention, FIG. 2 is a block diagram showing an example of a lens moving mechanism of an autofocus device, and FIG. 3 is a block diagram showing an example of a lens moving mechanism of an autofocus device. A timing chart showing the origin detection operation, FIG. 4 is a configuration diagram showing the embodiment of FIG. 1 in more detail using an autofocus device as an example, and FIG. 5 shows the substitute positioning operation in the embodiment of FIG. 4. Flowchart, FIG. 6 is a flowchart showing the origin detection operation, FIG. 7 is a block diagram showing a specific example of the step-out detection section of the pulse motor in FIG. 1, and FIG. 8 is a timing chart showing the operation of this specific example. 9 to 1 are timing charts showing the step-out correction operation of the pulse motor in the embodiment shown in FIG. 1, respectively. 1... Control circuit, 2... Pulse motor, 3... Detector, 4... Drive circuit, 5... Input device, 7... Lens position control circuit, 8... ■Adjustment Switch, 9...
Power supply, 10... Adjuster, 11... Focusing lens, 13... Setting circuit, 4... Expected rotation detection circuit, 15... Rotation detection circuit,] 6... Comparison circuit,
21...Feed screw part, 22...Table, 31.3
2...Detector. Figure 2 (CL) (α) also I meeting θ Ha'+Lsu (shi) 4 Moxibustion earthenware 31 appearance n (c) 4 Tora Toga [32 no 1 soil η (cLI P2 Kushi P3 Figure Figure 5 Diagram

Claims (1)

[Scope of Claims] 1. A pulse motor drive device that rotationally drives a pulse motor using drive pulses from a drive circuit and includes a detection means for detecting the rotation of the pulse motor, in which the detection pulses of the detection means are supplied. 1. A drive device for a pulse motor, comprising step-out detection means for detecting step-out of the pulse motor and outputting a step-out detection signal. 2. In claim 1, the step-out detection means predicts the generation timing of the detection pulse of the detector, and forms and outputs a predicted rotation detection pulse from the drive pulse at the predicted generation timing of the detection pulse. A pulse motor comprising: a rotation detection circuit; and a comparison circuit that detects a phase relationship between the detection pulse and the expected rotation detection pulse and outputs the step-out detection signal representing a phase mismatch between these pulses. drive unit. 3. The step-out correction signal according to claim 2, further comprising means for generating the step-out correction signal at the timing of generation of the first detection pulse after the generation of the step-out detection signal, including when the step-out detection signal of the step-out detection means is generated. Pulse motor drive device. 4. In claim 3, the first rotation amount of the pulse motor from generation of the last expected rotation detection pulse preceding the step-out correction signal until generation of the step-out correction signal; a first means for calculating a second rotation amount of the pulse motor from the generation of the adjustment correction signal to the expected first predicted rotation detection pulse; step-out correction means comprising second means for determining the magnitude relationship of rotation amounts and selecting the smaller rotation amount; and means for shifting the generation timing of the predicted rotation detection pulse according to the selected rotation amount. A pulse motor drive device comprising: 5. A motor position detection circuit that detects the motor position by counting the drive pulses of the pulse motor, and predicts the motor position where the expected rotation detection pulse indicated by the smaller of the first and second rotation amounts will be generated. The motor position correction means includes a motor position prediction circuit for correction, and a motor position resetting circuit that sets the motor position for correction to the motor position of the motor position detection circuit in response to generation of the step-out correction signal. A pulse motor drive device characterized by: