JP3792644B2 - Scan motor and scan motor control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scan motor and a scan motor control method.
[0002]
[Prior art]
Conventionally, the frequency and phase of the drive power supply can automatically follow the mechanical resonance frequency and phase of the oscillating mirror without using a sensor, minimizing power consumption and reducing the operating voltage. There is a drive circuit for a vibrating mirror type scanning device capable of expanding the range (see, for example, Patent Document 1).
[0003]
Further, the comparator determines the laser irradiation start timing and stop timing within one scanning period based on the register setting and the counter value, and the mask signal generation circuit and the AND gate determine 1 based on the start / stop timing. There is a laser scanning bar code reader that generates a laser irradiation ON / OFF signal that is turned on / off within a scanning period and controls turning on / off of the laser beam within one scan (see, for example, Patent Document 2).
[0004]
In addition, a position sensor is provided at the boundary position of the scan width where the light reflected by the reflecting mirror fixed integrally with the scan motor is projected and scanned, and the reflected light is incident on and received by this position sensor. There is a scan motor control method that increases the current output time and corrects the reduction in the vibration width of the scan motor due to temperature increase or voltage decrease (see, for example, Patent Document 3).
[0005]
Further, in a scanning microscope in which an optical system for irradiating the illumination light onto the sample is held at the tip of the tuning fork and the tuning fork is vibrated by a vibrating means to scan the illumination light on the sample, the tip of the tuning fork and There is an apparatus that controls a change in amplitude by measuring a leakage magnetic flux between an electromagnet and a Hall element to detect an amplitude of a tuning fork (see, for example, Patent Document 4).
[0006]
Of the four polygon motors of the color image forming apparatus, the reference polygon motor is provided with one hall element for detecting the rotational position, and the other polygon motors are shifted in position by five hall elements. When the polygon motor is PLL-controlled and the image is written at a constant rotational speed, if a color shift occurs in the formed image, the polygon motor is switched and the comparison frequency is output from the polygon motor. There is a laser beam scanning device that corrects color misregistration by switching the phases of these and performing PLL control to match the mirror surfaces of the rotating polygon mirrors (see, for example, Patent Document 5).
[0007]
In addition, it has a laser unit arranged at a fixed position, a collimating lens arranged in front of the laser unit, and a magnetically driven oscillating mechanism that oscillates the collimating lens left and right. Is detected based on the output of the Hall element that detects the origin of the rotational position of the rotor of the swing mechanism, and there is a beam scanning device in which the light emission timing of the laser unit is feedback controlled based on this (for example, see Patent Document 6). .
[0008]
[Patent Document 1]
JP 10-209773 A [Patent Document 2]
JP 2000-11084 A [Patent Document 3]
JP 2000-292731 A [Patent Document 4]
JP-A-4-296811 [Patent Document 5]
Japanese Patent Laid-Open No. 10-20228 [Patent Document 6]
Japanese Patent Laid-Open No. 11-352434
[Problems to be solved by the invention]
The scan motor needs to be controlled because the vibration width fluctuates due to a temperature change. In the above-described conventional technology, control is performed by an optical sensor or a circuit. However, the control by the optical sensor restricts the swing angle for observing the laser or enlarges the entire apparatus. Since the control by the circuit is a complicated circuit, it is difficult to reduce the size of the apparatus.
[0010]
In the prior art of Patent Document 3, the scanning of the scanning motor is changed by receiving the scanning laser beam. However, since the physical position is required, the scanning width is changed and the control is performed beyond the physical sensor position. Is impossible to do. That is, in the case of a physical sensor, control is performed by fixing the position depending on whether light enters or does not enter the sensor. Therefore, it is impossible to change whether the scanning width is to be reduced or widened.
[0011]
In view of the above-described problems of the conventional technology, an object of the present invention is to provide a scan motor and a scan motor control method capable of downsizing the entire apparatus.
[0012]
[Means for Solving the Problems]
The scan motor of the present invention is
It consists of a mirror, a rotor including a magnet, a coil including a yoke for moving the rotor, a Hall element between the magnet and the coil, a drive unit, and a control unit. The control unit is obtained from the Hall element. The rotor vibration width is detected from the obtained signal level, and a control signal is output to the drive unit by varying the amount of energy applied to the coil so that a constant vibration width is obtained. The drive unit is output from the control unit. The signal is input and the drive signal is output to the coil.
[0013]
The control unit includes a comparator, a comparator, and a correction unit. The comparator determines the pulse width of the signal obtained from the Hall element using a threshold line, and compares the determined pulse width with the comparator. The comparator compares the pulse width with a reference value corresponding to a preset vibration width, and outputs a difference between the pulse width and the reference value to the correction unit. The correction amount may be calculated, and a signal obtained by adding the correction amount to the signal before correction may be output to the drive unit, and the drive unit may input the signal output from the correction unit and output the drive signal to the coil.
[0014]
Further, when the control unit detects the vibration width of the rotor from the signal level obtained from the Hall element, the left and right vibrations of the rotor may be observed, and left and right individual control may be performed.
[0015]
The method for controlling the scan motor of the present invention includes:
A scan motor control method comprising a mirror, a rotor including a magnet, a coil including a yoke for moving the rotor, a Hall element between the magnet and the coil, a drive unit, and a control unit. The control unit detects the vibration width of the rotor from the signal level obtained from the Hall element, and outputs a control signal by varying the amount of energy applied to the coil so as to be a constant vibration width, The drive unit inputs a signal output from the control unit and outputs a drive signal to the coil.
[0016]
The control unit is a method for controlling a scan motor including a comparator, a comparator, and a correction unit. The comparator determines a pulse width of a signal obtained from the Hall element using a threshold line. The determined pulse width is output to the comparator, the comparator compares the pulse width with a reference value corresponding to a preset vibration width, and outputs the difference between the pulse width and the reference value to the correction unit, The correction unit calculates the correction amount from the input difference, outputs a signal obtained by adding the correction amount to the signal before correction to the drive unit, and inputs the signal output from the correction unit by the drive unit to the coil. A drive signal may be output.
[0017]
In addition, when the control unit detects the vibration width of the rotor from the signal level obtained from the Hall element, the left and right vibrations of the rotor may be observed and the left and right vibrations may be controlled separately. Since the sensor unit is incorporated and controlled, it is not necessary to install a sensor outside, and the entire apparatus can be downsized. When the sensor is not used, the control circuit becomes very complicated and the circuit scale becomes large. On the other hand, when the Hall element is used, the circuit can be simplified.
[0018]
In addition, when the control is performed by the Hall element, both the left and right operations can be observed, so that the left and right individual control can be performed and a more stable vibration width can be obtained.
[0019]
In the conventional technology, the scanning motor scan is changed by receiving the scanning laser beam. However, since the physical position is required, the scanning width is changed and the control is performed beyond the physical sensor position. However, since the present invention is for observing a change in the magnetic field with a Hall element, there is no physical limit even if there is a limit of sensitivity. Infinite control is possible. That is, in the case of a physical sensor, control is performed by fixing the position depending on whether or not light enters the sensor. However, the present invention can be varied regardless of whether the scanning width is to be reduced or widened.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration of a scan motor according to an embodiment of the present invention.
[0021]
FIG. 1 shows a configuration of a rotor 201 including a mirror 101 and a magnet 102 and a coil 202 for moving the rotor 201, as compared with the configuration of the magnet 102 and the coil 202 of the rotor 201, as shown in the scan motor according to the embodiment of the present invention. A Hall element 203 is provided between the two.
[0022]
In the scan motor control method according to the embodiment of the present invention, the vibration width of the rotor 201 is detected from the signal level obtained from the Hall element 203, and the amount of energy applied to the coil 202 is varied so as to have a constant vibration width. Is.
[0023]
Referring to FIG. 1, the scan motor includes a mirror 101, a rotor 201 including a magnet 102, a coil 202 including a yoke 103 for moving the rotor 201, a hall element 203, a drive unit 204, and a control unit 205. In this control method, the signal level obtained from the Hall element 203 is checked by the control unit, and the drive signal aa-1 or aa-2 output from the drive unit is controlled.
[0024]
FIG. 2 is a block diagram showing the configuration of the control unit 205 in the embodiment of the present invention. The control unit 205 includes a comparator 106, a comparator 104, and a correction unit 105. The control unit 205 inputs a signal cc obtained from the Hall element 203 to the comparator 106, and determines a pulse width by using a threshold line ee. This pulse width is compared with a reference value bb corresponding to a preset vibration width by the comparator 104, and the difference from the reference value bb is input to the correction unit 105.
[0025]
The correction unit 105 calculates a correction amount from the difference from the input reference value bb, and outputs a signal dd obtained by adding the correction amount to the signal before correction to the drive unit 204.
[0026]
The drive unit 204 receives the signal dd output from the correction unit 105 and outputs a drive signal aa-1 or aa-2 to the coil 202.
[0027]
A scan motor control method according to an embodiment of the present invention will be described with reference to FIG.
[0028]
The scan motor inputs the drive signal aa-1 or aa-2 output from the drive unit 204 to the coil 202, and thereby attracts the magnet 102 attached to the rotor 201 by a change in magnetic flux generated from the yoke 103. Alternatively, the mirror 101 is vibrated by a repulsive force, and the irradiated laser is reflected and scanned. The hall element 203 is installed between the yoke 103 and the magnet 102.
[0029]
FIG. 3 shows an output signal value cc of the Hall element 203 when the mirror 101 vibrates due to attraction and repulsion of the magnet 102 attached to the rotor 201. A1 is a state in which the rotor 201 oscillates to one side to the maximum when the drive signal aa-1 is input from the drive unit 204. A2 is a signal value output from the Hall element 203 in the state of A1. B1 is a state in which the rotor 201 is vibrated to the maximum when the drive signal aa-2 is input from the drive unit 204. B2 is a signal value cc output from the Hall element 203 in the state of B1. C1 is an operation start point, and is a passing point when vibration is repeated from A1 to B1 or from B1 to A1, and is the maximum position of the magnetic flux detected by the Hall element 203. C2 is a signal value cc output from the Hall element 203 in the state of C1.
[0030]
FIG. 4 shows changes in the set swing angles α 0 to α 2 in a state where the rotor 201 is oscillated to one side to the maximum.
[0031]
FIG. 5 shows a change in the output signal value cc of the Hall element 203 with respect to the vibration width. The swing angle α 1 is larger than the set swing angle α 0, and the swing angle α 2 is smaller than α 0.
[0032]
Further, output signal values cc from the Hall element 203 in the case of the swing angles α 0, α 1, and α 2 are shown in FIGS. When the swing angle is large, the amplitude of the output signal value cc from the Hall element 203 is large, and when the swing angle is small, the amplitude is small. The signal value cc output from the Hall element 203 determines the pulse width based on the threshold line ee set in advance by the comparator 106. The determined pulse width ff is compared with the reference value bb by the comparator 104, and the difference gg from the reference value bb is output to the correction unit 105. The correction unit 105 calculates the correction amount based on the difference from the reference value bb, and outputs a signal dd obtained by adding the correction amount to the signal before correction to the drive unit 204. The drive unit 204 receives the signal dd output from the correction unit 105 and outputs a drive signal aa-1 or aa-2 to the coil 202.
[0033]
【The invention's effect】
As described above, the present invention has the following effects.
[0034]
Since the sensor unit is incorporated and controlled in the scan motor, there is no need to install a sensor outside, and the entire apparatus can be downsized. Further, when the sensor is not used, the control circuit becomes very complicated and the circuit scale becomes large. On the other hand, when the Hall element is used, the circuit can be simplified.
[0035]
Further, when the control is performed by the Hall element, both the left and right operations can be observed, so that the left and right individual control can be performed, and there is an effect that a more stable vibration width can be obtained.
[0036]
In the conventional technology, the scanning motor scan is changed by receiving the scanning laser beam. However, since the physical position is required, the scanning width is changed and the control is performed beyond the physical sensor position. However, since the present invention is for observing a change in the magnetic field with a Hall element, there is no physical limit even if there is a limit of sensitivity. Infinite control is possible. That is, in the case of a physical sensor, control is performed by fixing the position depending on whether or not light enters the sensor. However, the present invention can be varied regardless of whether the scanning width is to be reduced or widened. There is.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a scan motor according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a control unit in the embodiment of the present invention.
FIG. 3 is a diagram showing an output signal value of a Hall element when a mirror vibrates due to attraction and repulsion of a magnet attached to a rotor.
FIG. 4 is a diagram showing changes in the set swing angles α 0 to α 2 in a state where the rotor vibrates to the maximum.
FIG. 5 is a diagram showing a change in the output signal value cc of the Hall element with respect to the vibration width.
[Explanation of symbols]
101 Mirror 102 Magnet 103 Yoke 104 Comparator 105 Correction Unit 106 Comparator 201 Rotor 202 Coil 203 Hall Element 204 Drive Unit 205 Control Unit
aa-1, aa-2 drive signal
bb reference value
cc Signal (value) output from Hall element
dd Signal with correction amount added to signal before correction
ee threshold line
ff Determined pulse width

Claims (6)

A rotor attached to one end, a magnet attached to the opposite end, and a rotor that vibrates left and right about one point between the mirror and the magnet ;
A coil including a yoke for vibrating the rotor left and right provided so that the longitudinal direction is perpendicular to the rotor and the magnet is positioned substantially at the center in the longitudinal direction ;
A hall element provided between the rotor and the coil , which outputs a signal for detecting left and right vibration width of the rotor , a drive unit, and a control unit,
The control unit detects a vibration width of the rotor from a signal level obtained from the Hall element, and controls a signal to be controlled by varying an amount of energy applied to the coil so that a constant vibration width is obtained. Output to
The drive unit receives a signal output from the control unit and outputs a drive signal to the coil. The control unit includes a comparator, a comparator, and a correction unit.
The comparator determines the pulse width of the signal obtained from the Hall element at a threshold line, and outputs the determined pulse width to the comparator.
The comparator compares the pulse width with a reference value corresponding to a preset vibration width, and outputs a difference between the pulse width and the reference value to the correction unit,
The correction unit calculates a correction amount from the input difference, and outputs a signal obtained by adding the correction amount to a signal before correction to the drive unit,
The scan motor according to claim 1, wherein the drive unit inputs a signal output from the correction unit and outputs a drive signal to the coil. When the control unit detects the vibration width of the rotor from the signal level obtained from the Hall element,
The scan motor according to claim 1, wherein left and right vibrations of the rotor are observed, and left and right individual control is performed. A rotor attached to one end, a magnet attached to the opposite end, and a rotor that vibrates left and right about one point between the mirror and the magnet ;
A coil including a yoke for vibrating the rotor left and right provided so that the longitudinal direction is perpendicular to the rotor and the magnet is positioned substantially at the center in the longitudinal direction ;
A scan motor control method comprising a Hall element provided between the rotor and the coil, a drive unit, and a control unit , which outputs a signal for detecting the left and right vibration width of the rotor. There,
The drive unit detects a vibration width of the rotor from the signal level obtained from the Hall element, and controls the drive unit to vary the amount of energy applied to the coil so as to obtain a constant vibration width. Output to
A method for controlling a scan motor, wherein the drive unit inputs a signal output from the control unit and outputs a drive signal to the coil. The control unit is a scan motor control method including a comparator, a comparator, and a correction unit,
The comparator obtains a signal obtained from the Hall element, determines a pulse width at a threshold line, and outputs the determined pulse width to the comparator.
The comparator compares the pulse width with a reference value corresponding to a preset vibration width, and outputs the difference between the pulse width and the reference value to the correction unit,
The correction unit calculates a correction amount from the input difference, and outputs a signal obtained by adding the correction amount to the signal before correction to the drive unit,
The scan motor control method according to claim 4, wherein the drive unit inputs a signal output from the correction unit and outputs a drive signal to the coil. When the control unit detects the vibration width of the rotor from the signal level obtained from the Hall element,
6. The scan motor control method according to claim 4, wherein left and right vibrations of the rotor are observed and left and right individual control is performed.

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