JP2013123325A - Motor drive unit, light-emitting device, and drive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor drive unit, a light-emitting device and a drive method capable of responding to a rapid change in speed.SOLUTION: A drive unit 40 of a motor 33 of the present invention is a drive unit 40 for a motor 33 which moves a light-emitting unit 20 emitting light to be irradiated upon the subject to a target position which is set on the basis of the movement amount of a photographing lens 2L. Whether the motor 33 is to be driven in a trapezoid drive mode in which the revolution speed of the motor 33 is raised at a prescribed change rate within a prescribed time after the start of drive, maintained at a certain number of revolutions thereafter, and then reduced at a prescribed change rate within a prescribed time after the end of drive, or a constant speed drive mode in which the revolution speed of the motor 33 is maintained at a certain number of revolutions is determined depending on the distance to the target position. The motor 33 is driven on the basis of this determination.

Description

  The present invention relates to a motor driving device, a light emitting device, and a driving method.

  Conventionally, as a motor drive device such as a stepping motor, the motor is driven by a so-called trapezoidal drive that starts from a low rotation at the time of acceleration to start the motor and shifts from high to low at the time of deceleration to stop the motor. Some drive (for example, refer to Patent Document 1).

JP-A-62-3700

  However, in the case of a motor that performs zooming of a light emitting device that illuminates a subject, it is necessary to arbitrarily and instantaneously drive the motor in conjunction with the zoom change of the lens on the camera side. In order to cope with such an arbitrary and instantaneous speed change, the trapezoidal drive as in the above-described prior art may hinder the operation.

  An object of the present invention is to provide a motor driving device, a light emitting device, and a driving method capable of responding to a rapid speed change.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

According to the first aspect of the present invention, the motor (33) that moves the light emitting unit (20) that emits the light to be irradiated to the subject toward the target position set based on the driving amount of the photographing lens (2L). In the driving device (40), after the rotational speed of the motor (33) is increased at a predetermined rate of change within a predetermined time after the start of driving, the constant rotational speed is maintained and the predetermined speed before the end of driving is reached. Whether the motor (33) is driven by trapezoidal driving that reduces the rotational speed at a predetermined rate of change in time or constant speed driving that maintains the rotational speed of the motor (33) at a constant rotational speed According to the distance to the target position, and the motor (33) is driven based on the determination, the drive device (40) for the motor (33).
Invention of Claim 2 is a drive device (40) of Claim 1, Comprising: The said target position changes before the movement of the said light emission part (20) to the set said target position is completed. If it is, whether the motor (33) is driven by the trapezoidal driving or the constant speed driving according to the distance between the position of the light emitting unit (20) and the new target position at the time of the change. It is a drive device (40) characterized by these.
A third aspect of the present invention is the drive device (40) according to the first aspect, wherein when the motor (33) is started, the current position of the light emitting unit (20) and the target position are The drive device (40) is characterized by determining whether to drive the motor (33) by either the trapezoidal drive or the constant speed drive according to a distance.
The invention according to claim 4 is the drive device (40) according to any one of claims 1 to 3, wherein the motor is a stepping motor (33). 40).
According to a fifth aspect of the present invention, a light emitting unit (20) that emits light to be irradiated on a subject, and the light emitting unit (20) toward a target position set based on a driving amount of a photographing lens (2L). A light emitting device including a motor (33) for moving the motor and a drive device (40) for driving the motor (33), wherein the drive device (40) is within a predetermined time after the start of driving. A trapezoidal drive that maintains a constant rotational speed after increasing the rotational speed of the motor (33) at a change rate, and decreases the rotational speed at a predetermined change rate within a predetermined time before the end of driving, or the motor It is determined according to the distance to the target position whether the motor (33) is driven by constant speed driving in which the rotational speed of (33) is maintained at a constant rotational speed, and based on the determination, the motor A light emitting device characterized by driving (33) That.
According to the sixth aspect of the present invention, the motor (33) that moves the light emitting section (20) that emits light to be irradiated to the subject toward the target position set based on the driving amount of the photographing lens (2L). In this driving method, after gradually increasing the rotational speed of the motor (33) at a predetermined rate of change within a predetermined time after the start of driving, the constant rotational speed is maintained and within a predetermined time before the end of driving. Whether the motor (33) is driven by trapezoidal driving for reducing the rotational speed at a predetermined rate of change or constant speed driving for maintaining the rotational speed of the motor (33) at a constant rotational speed. The method of driving the motor (33) is characterized in that the determination is made according to the distance to the position, and the motor (33) is driven based on the determination.
Note that the configuration described with reference numerals may be modified as appropriate, and at least a part of the configuration may be replaced with another component.

  According to the present invention, it is possible to provide a motor driving device, a light emitting device, and a driving method capable of responding to a rapid speed change.

It is a side view which shows notionally the structure of the illuminating device to which one Embodiment of this invention is applied. It is a control flowchart of the moving mechanism by a control part. (A) is a sequence diagram showing an input pulse to the drive motor during normal control, and (b) is a rotational speed transition diagram of the drive motor. (A) is a rotational speed transition diagram of the drive motor at the time of situation control, and (b) is a rotational speed transition diagram of the drive motor at the time of normal control under the same conditions as (a) as a comparative example. It is a rotational speed transition diagram of the drive motor at the time of situation corresponding control of other drive conditions.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view conceptually showing the structure of a lighting apparatus 10 to which an embodiment of the present invention is applied. As shown in FIG. 1, the illumination device 10 according to this embodiment is detachably attached to the camera 1.
In the following description, when the illumination device 10 is viewed from the subject side irradiated with light (from the front side), the right direction is the X axis plus direction, the upper direction of the illumination device 10 is the Y axis plus direction, A direction in which light orthogonal to the X axis and the Y axis is irradiated is a Z axis plus direction. The Z-axis plus side is referred to as the front side, and the Z-axis minus side is referred to as the back side.

  When the illumination device 10 shown in FIG. 1 is attached to the accessory shoe 1S of the camera body 1B in the camera 1, it is connected to the control device 1C included in the camera body 1B via the terminal 13 and input from the control device 1C. The illumination angle of the emitted light (illumination light) can be changed corresponding to the focal length information of the lens barrel 2 (having a so-called zoom function).

In FIG. 1, a camera 1 to which a lighting device 10 is attached is constituted by a camera body 1 </ b> B and a lens barrel 2. The lens barrel 2 is a so-called zoom lens in which a plurality of lens groups 2L are moved in the optical axis direction with a predetermined relationship by rotating an operation ring 2A provided on the outer periphery, and the focal length is changed. The zooming information (the rotation operation amount of the operation ring 2A or the movement amount of the lens group 2L) detected by the sensor 2S is output to the control device 1C of the camera body 1B via the lens control unit 2C. The control device 1 </ b> C calculates a focal length based on zooming information input from the lens barrel 2 and outputs the focal length to the illumination device 10.
The illumination device 10 changes the irradiation angle of the light emission (illumination light) of the light emitting unit 20 based on the focal length information of the lens barrel 2 input from the camera 1 (control device 1C). It should be noted that the lens barrel 2 may be either detachable from or integrated with the camera body 1B.

  The illumination device 10 includes a light emitting unit 20 that generates flash light, a moving mechanism 30 that moves and drives the light emitting unit 20, a control unit 40, a light emission driving circuit 41 of the light emitting unit 20, and a movement driving circuit 42 of the moving mechanism 30. It is equipped with. A Fresnel lens 11 is provided on the front side of the light emitting unit 20. Moreover, the illuminating device 10 is provided with the leg part 12 with which the accessory shoe 1S of the camera main body 1B, a tripod, etc. are mounted | worn at a lower end part. The leg 12 is provided with a terminal 13 connected to the control unit 40. When the terminal 13 is attached to the accessory shoe 1S of the camera 1, the control unit 40 and the control device 1C of the camera 1 are connected via the terminal 13. It is connected so that information can be exchanged. Furthermore, although not illustrated, the illuminating device 10 includes a power source that supplies electric power to each component in the illuminating device 10.

The light emitting unit 20 includes a xenon tube 21 disposed in parallel with the X axis, and a reflector 22 disposed on the back side of the xenon tube 21. The light emitting unit 20 is provided so as to be movable in the front-rear direction (Z-axis direction) by being guided by a guide member (not shown).
The moving mechanism 30 includes a wire spring 31 fixed to the lower surface of the light emitting unit 20, a drive screw 32, and a drive motor 33 that rotationally drives the drive screw 32.

  The wire spring 31 is fixed to the lower surface of the light emitting unit 20 with a screw, and is engaged with the valley of the screw of the drive screw 32 by its elastic return force, and is moved and driven by the displacement of the engagement portion by the rotation of the drive screw 32. Is done. That is, the wire spring 31 functions in the same manner as a female screw that is screwed into the drive screw 32.

  The drive screw 32 is disposed in parallel with the Z axis, and moves and drives the wire spring 31 (that is, the light emitting unit 20) in the Z axis direction by rotation. In the present embodiment, the drive screw 32 is formed as a right-hand screw, and the light emitting unit 20 is rotated in the Z-axis minus direction (back side: right side in the figure) by clockwise rotation when viewed from the drive motor 33 side (back side). The light emitting unit 20 is driven to move in the positive direction of the Z axis (front side: left side in the figure) by counterclockwise rotation.

  The drive motor 33 is a two-phase stepping motor in this embodiment. The rotation shaft of the drive motor 33 is connected to the drive screw 32. The drive motor 33 is driven by a current supplied from a movement drive circuit 42 controlled by the control unit 40 described later, and rotationally drives the drive screw 32. The drive terminals of the drive motor 33 are composed of A, -A, B, and -B, which are A phase and B phase, respectively, and A, -A, B, and -B are inverted signals.

  The moving mechanism 30 moves and drives the light emitting unit 20 back and forth by the rotational drive of the drive screw 32 by the drive motor 33. The movement of the light emitting unit 20 changes the distance between the light emitting unit 20 and the Fresnel lens 11F, and as a result, the illumination angle of illumination light irradiated to the outside through the Fresnel lens 11F changes.

  The control unit 40 is configured by a microcomputer or the like, and comprehensively controls the lighting device 10. For example, the control unit 40 controls the light emission operation of the light emitting unit 20 via a light emission drive circuit 41 described later based on a light emission command from the camera 1 and drives the moving mechanism 30 via a movement drive circuit 42 described later. Then, the change of the illumination angle of the illumination light according to the focal length of the camera 1 (lens barrel 2) is controlled.

  The light emission drive circuit 41 includes a capacitor that supplies power for light emission to the light emitting unit 20, a boosting unit that boosts a power supply voltage to supply charging energy to the capacitor, and the like, and is controlled by the control unit 40 to be light emitting unit 20. Drive.

  The movement drive circuit 42 generates a sinusoidal drive current for microstep driving the drive motor 33 based on a command from the control unit 40, and supplies the drive current to the drive motor 33. The cycle of the drive current generated by the movement drive circuit 42 is variable according to the command from the control unit 40.

  When the lighting apparatus 10 configured as described above receives a control command from the control device 1C included in the camera body 1B via the terminal 13, the control unit 40 drives to emit light based on the control command as described above. The light emitting operation of the light emitting unit 20 is controlled via the circuit 41, and the moving mechanism 30 is driven via the movement driving circuit 42 so as to correspond to the focal length (angle of view) of the camera 1 (lens barrel 2). Change and control the irradiation angle of light.

  Here, the illumination angle of the illumination light is changed by the control unit 40 by moving the light emitting unit 20 back and forth by driving the moving mechanism 30 via the movement driving circuit 42 as described above. When the zooming operation to the lens barrel 2 is frequent in small increments (during troublesome operation), the unit 40 performs drive control (situation control) different from the normal time (normal control). The discrimination between the normal time and the troublesome operation is performed based on the distance between the current position of the light emitting unit 20 and the target position (using the number of pulses of the drive motor 33 as an index).

Next, with reference to FIGS. 2 to 5, drive control of the moving mechanism 30 according to the zooming operation in the lens barrel 2 by the control unit 40 will be described.
FIG. 2 is a control flowchart of the moving mechanism 30 by the control unit 40. FIG. 3A is a sequence diagram showing input pulses to the drive motor 33 during normal control, and FIG. 3B is a rotational speed transition diagram of the drive motor 33. FIG. 4A is a rotational speed transition diagram of the drive motor 33 at the time of situational control, and FIG. 4B is a rotational speed transition diagram of the drive motor 33 at the time of normal control under the same conditions as (a) as a comparative example. FIG. 5 is a rotational speed transition diagram of the drive motor 33 at the time of situation corresponding control under different drive conditions.

  First, drive control of the moving mechanism 30 corresponding to the zooming operation of the lens barrel 2 by the control unit 40 will be described along the flowchart shown in FIG. In the following description and FIG. 2, step is also abbreviated as “S”.

When the power is turned on and zoom operation information is input from the camera 1 (S201), the control unit 40 moves the light emitting unit 20 to a target position corresponding to the zoom operation (the irradiation angle corresponding to the focal length of the lens barrel 2). The number of driving pulses Px of the driving motor 33 in the moving mechanism 30 necessary for moving to (position) is calculated (S202).
Then, the number of drive pulses: Px is compared with the number of determination pulses: Ps (S203). The number of determination pulses: Ps represents the threshold value of the distance between the current position of the light emitting unit 20 and the target position for determining the troublesome operation by the number of pulses of the drive motor 33, and is set to 80 pulses, for example.

In step 203, when the drive pulse number Px to the target position is larger than the determination pulse number Ps (No), the drive motor 33 is driven by normal control.
On the other hand, in step 203, when the number of drive pulses to the target position: Px is less than the number of determination pulses: Ps (Yes), the drive motor 33 is driven by the situation corresponding control.

  In the normal control, trapezoidal driving is performed in which the rotational speed is gradually changed as shown in FIG. 3A (-A and -B are not shown) at the start and end of driving. That is, when the drive of the drive motor 33 is started, the pulse mode of the stop position is output first. Next, a pulse in the rotation direction mode (CW = clockwise) is output. At this time, a low frequency (300 pps) is first output as the drive frequency, and the frequency is gradually increased, and finally, the drive frequency is shifted to a constant speed drive of a high frequency (1000 pps). When stopping, the high frequency (1000 pps) shifts to the low frequency (300 pps). The same applies to reverse rotation (CCW = counterclockwise).

By such rotation control, the rotation speed of the drive motor 33 is 0 pps (stopped) when not rotating only by energization, as shown in FIG. 3B, and increases from 300 pps to 1000 pps when starting to rotate. . For example, it rises from 300 pps to 1000 pps in 40 ms (80 pps).
Then, after rotating at a constant speed of 1000 pps, the rotational speed decreases from 1000 pps to 300 pps before stopping, and becomes 0 pps when stopped.
In the figure, for the sake of convenience, the reverse rotation is displayed so as to increase the rotation speed in the opposite direction.

  On the other hand, in the situation corresponding control, when the target position frequently changes due to a small zooming operation, such as when determining the composition, the trapezoidal driving that gradually changes the rotation speed is not performed, but the constant speed driving is performed. However, the constant speed drive is lower than the constant speed drive (1000 pps) in the normal control, for example, 400 pps.

  That is, as shown in FIG. 4B, when the conventional trapezoidal drive is performed, when the target position change instruction is input from the camera 1 during the drive (during the stop trapezoidal drive toward the target position), the start trapezoidal drive is performed again. The rotational speed fluctuates. Further, when a target position change instruction is input, the rotational speed changes again to shift to start-up driving again. As a result, the light emitting unit 20 and the moving mechanism 30 may be vibrated and sound may be generated.

  On the other hand, as shown in FIG. 4 (a), the situation corresponding control is a determination pulse in which the number of drive pulses: Px from the current position to the changed target position is a threshold value, depending on the positional relationship from the current position to the target position. When the number is less than Ps (the number of drive pulses: Px <the number of determination pulses: Ps), the operation shifts to the constant speed drive (400 pps) and drives to the target position.

  That is, in the example shown in FIG. 4A, since the number of drive pulses: Px is larger than the determination pulse number: Ps (drive pulse number: Px> number of determination pulses: Ps) at the time of activation, the trapezoid for normal control is used. Drive. If the target position is changed midway (zoom position change (1)), the number of drive pulses up to the target position is compared with the number of determination pulses: Ps, and the number of drive pulses: Px satisfies the number of determination pulses: Ps. Therefore, if the zoom position change (2) is entered during the transition to constant speed driving (400 pps) and the zoom position change (2) is entered midway, the same determination is made and constant speed driving is performed. In the change (3), the same judgment is made, and as a result, the constant speed driving is 400 pps. With such situation-related control, driving with less vibration and noise can be performed.

  In the example of FIG. 4A, at the time of start-up, after entering the normal control once, the process proceeds to the situation control. However, the distance from the current position of the light emitting unit 20 to the target position and the threshold value are set. Depending on the relationship, as shown in FIG. 5, a constant speed drive of 400 pps for situational control is performed without entering normal control. FIG. 5 is a diagram based on the premise that a zoom position change command similar to that in FIG. 4A has been entered, but the threshold value of the distance from the current position of the light emitting unit 20 to the target position for determining the situational control ( In this example, the number of determination pulses (Ps) is set larger than that in the case of FIG. 4A, and the target position is within the range of the situation corresponding control at the time of the first drive (drive pulse number: Px> determination). The number of pulses is Ps), and constant speed driving is performed in response control over the entire area.

As described above, this embodiment has the following effects.
In the illuminating device 10 according to the present embodiment, when changing the illumination angle of the illumination light by moving the light emitting unit 20 back and forth by the moving mechanism 30, the target position is frequently changed by a small zooming operation such as when determining the composition. In such a case, the drive motor 33 in the moving mechanism 30 is driven at a constant speed by the situation corresponding control. As a result, even when the target position frequently changes due to a small zooming operation, acceleration / deceleration vibration can be suppressed and noise generation can be suppressed. As a result, malfunctions can be reduced, and durability can be improved by reducing the load acting on the moving mechanism 30 and the light emitting unit 20.

(Deformation)
The present invention is not limited to the above-described embodiment, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.
(1) In the present embodiment, 80 pulses are exemplified as the determination threshold value for normal control during normal time and situational control during troublesome operation, but the determination threshold value is not limited to this and can be set as appropriate.

(2) The said embodiment is an example which applied this invention to the illuminating device 10 which the xenon tube 21 light-emits. However, the present invention is not limited to this. For example, the present invention may be used for an illumination device that emits light from an LED.
In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited to the embodiment described above.

  1: camera, 2: lens barrel, 2L: lens group, 210: illumination device, 20: light emitting unit, 30: moving mechanism, 33: drive motor 33, 40: control unit

Claims (6)

A motor driving device that moves a light emitting unit that emits light to irradiate a subject toward a target position set based on a driving amount of a photographing lens,
After increasing the rotation speed of the motor at a predetermined change rate within a predetermined time after the start of driving, maintaining a constant rotation speed, and decreasing the rotation speed at a predetermined change rate within a predetermined time before the end of driving It is determined according to the distance to the target position whether to drive the motor by trapezoidal driving or constant speed driving that maintains the rotational speed of the motor at a constant rotational speed,
A motor driving device that drives the motor based on the determination. The drive device according to claim 1,
When the target position is changed before the movement of the light emitting unit to the set target position is completed, according to the distance between the position of the light emitting unit and the new target position at the time of the change, Determining whether to drive the motor with the trapezoidal drive or the constant speed drive;
A drive device characterized by the above. The drive device according to claim 1,
Determining whether to drive the motor by either the trapezoidal driving or the constant speed driving according to the distance between the current position of the light emitting unit and the target position at the start of driving the motor;
A drive device characterized by the above. The drive device according to any one of claims 1 to 3,
The motor is a stepping motor;
A drive device characterized by the above. A light emitting unit that emits light to irradiate the subject;
A motor for moving the light emitting unit toward a target position set based on a driving amount of the photographing lens;
A driving device for driving the motor, and a light emitting device comprising:
The drive device increases the rotation speed of the motor at a predetermined change rate within a predetermined time after the start of driving, then maintains a constant rotation speed, and at a predetermined change rate within a predetermined time before the end of driving. It is determined according to the distance to the target position whether the motor is driven by trapezoidal driving for reducing the rotational speed or constant speed driving for maintaining the rotational speed of the motor at a constant rotational speed, Driving the motor based on the determination;
A light emitting device characterized by the above. In a motor driving method of moving a light emitting unit that emits light to irradiate a subject toward a target position set based on a driving amount of a photographing lens,
After gradually increasing the rotational speed of the motor at a predetermined change rate within a predetermined time after the start of driving, the constant rotational speed is maintained, and the rotational speed is adjusted at a predetermined change rate within a predetermined time before the end of driving. It is determined according to the distance to the target position which of the trapezoidal drive to decrease or the constant speed drive that maintains the rotation speed of the motor at a constant rotation speed,
A motor driving method comprising driving the motor based on the determination.

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