JP2009116137A - Rocking body apparatus and equipment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rocking body apparatus in which the neutral position of the rocking body is adjusted, so that the irradiation position of a reflected light beam and the distance between the irradiation position and an object are adjustable. <P>SOLUTION: The rocking body apparatus has: a rocking body 1 supported rockably around a rocking shaft 2 interposing the neutral position; driving means 4, 5, and 6; and position adjustment means 4, 7 and 8. The driving means is a means for rocking the rocking body 1 around the rocking shaft 2, and the position adjustment means is a means for adjusting the neutral position of the rocking body 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an oscillating body device including an oscillating body supported so as to be oscillatable around an oscillating shaft, an optical scanner using the oscillating body that deflects and scans light emitted from a light source at an appropriate frequency, and potential measurement. The present invention relates to a device such as a potential sensor that measures the potential of a target.

A function of scanning a laser beam or the like at a predetermined frequency is incorporated in an image reader, an OCR (optical character reader), a barcode reader, an LBP (laser beam printer), or the like. As one that bears such a function, there has been proposed an optical scanner that resonates and vibrates a mirror made of silicon or the like at a predetermined frequency by an electromagnetic actuator (see Patent Document 1).

In such an optical scanner, for example, a permanent magnet is mounted on a silicon mirror, and an alternating current according to the resonance frequency of the mirror is applied to an excitation coil arranged opposite to the permanent magnet to bring the mirror into a resonance state. The incident light beam is scanned.

On the other hand, in an image reader using an optical scanner, an LBP, or the like, the position where a scanned beam is hit is very important. The positioning accuracy of the optical system that determines the position where the light strikes is determined by mechanical accuracy.
Japanese Patent Laid-Open No. 2002-311372

However, the above-mentioned mechanical positioning accuracy is limited, and in order to arrange the optical system with good accuracy, it is necessary to use a high-precision alignment means and adjust it. Further, in order to maintain the adjustment, it is necessary to use a material that does not cause deformation due to temperature, time, etc., which increases the cost.

In view of the above problems, an oscillator device according to the present invention includes an oscillator that is supported so as to be able to swing around an axis of swing across a neutral position, a drive means, and a position adjusting means. To do. The drive means is means for swinging the swinging body around a swing shaft, and the position adjusting means is means for adjusting a neutral position of the swinging body.

Further, in view of the above problems, the oscillator device of the present invention includes an oscillator that is supported so as to be able to swing around a swing shaft across a neutral position, and swings the swing body around the swing shaft. And an actuator for causing The actuator includes a coil and a permanent magnet provided to face each other, and adjusts a neutral position of the oscillating body by applying a current obtained by superimposing a modulation current and a direct current to the coil, and the oscillating body. Is characterized by rocking.

In view of the above problems, an optical scanner according to the present invention includes the oscillator device described above, and the oscillator is provided with an optical deflection element that deflects and scans a light beam.

Further, in view of the above problems, the potential sensor of the present invention includes the oscillator device described above, and induced charges corresponding to the potential of the potential measurement object are induced in the oscillator arranged to face the potential measurement object. The detection electrode is provided.

According to the oscillator device of the present invention, since the neutral position of the oscillator can be adjusted, in an optical scanner using the oscillator, the accuracy of the position where the light beam strikes can be improved. Also, in the potential sensor using the oscillator device of the present invention, the distance from the measurement object to the neutral position of the oscillator can be adjusted, so that more accurate potential measurement can be performed.

Embodiments of the present invention will be described below. One embodiment of the oscillator device of the present invention basically includes an oscillator that is supported so as to be able to swing around an oscillation shaft defined by an elastic support portion such as a torsion spring with a neutral position interposed therebetween, A driving actuator and a position adjusting actuator; The drive actuator that is the drive means is for swinging the swinging body around the swing shaft, and the position adjustment actuator that is the position adjusting means is for adjusting the neutral position of the swinging body. is there. The neutral position is a position taken by the oscillating body when the driving actuator is not working. When the oscillating shaft is defined by the elastic support part, the elastic support part is not elastically deformed at the neutral position.

The rocking body can take various forms. In one embodiment, as in the embodiment shown in FIG. 1 to be described later, one oscillating body 1 is swingably supported by a support beam 2 such as a pair of torsion springs. In another embodiment, as shown in FIG. 7 which is a top view, a plurality of swinging bodies 301 and 301a are supported swingably by elastic beams 304 and 304a. Here, the oscillating body 301 is formed with a reflective surface, and reflects and deflects incident light thereto. The other pair of oscillating bodies 301a are driver elements, to which bar magnets (not shown) are respectively fixed. A pair of elastic beams 304 are connected between the frame-shaped support substrate 302 and the driver, and a pair of elastic beams 304a are connected between the driver and the swinging body 301 so as to coincide with the swinging shaft 300, respectively. Has been. With such a configuration, it is possible to realize a swing motion in which the components of the two torsional resonance frequencies f and 2f are combined. By combining the components of f and 2f under appropriate phase and amplitude conditions, it is possible to cause the oscillating body with a reflecting surface 301 to perform an oscillating motion having a constant angular velocity part. Since the pair of driver elements 301a are vibrated in the same phase, the torsional rigidity of the corresponding pair of elastic beams 304 and 304a and the moment of inertia of the corresponding pair of driver elements 301a are aligned. Thus, an alternating magnetic force having the same phase is applied to each bar magnet from an exciting coil (not shown), and the oscillating body 301 is oscillated. In this configuration, the bar magnet and the exciting coil constitute a driving actuator. By providing the position adjusting actuator in this configuration, the elastic beams 304 and 304a are bent to adjust their positions, and the neutral position of the swinging body 301 can be adjusted. The position adjusting actuator can be constituted by, for example, the bar magnet and a correction coil for applying a direct current.

In the above embodiment, the oscillating body is supported by a double-supported beam type. However, as shown in FIG. 8, a plurality of oscillating bodies 301 and 301a (or one oscillating body) can be oscillated by elastic beams 304 and 304a. Can be supported by a cantilever type. In the case of a cantilever type as shown in FIG. 8, the support substrate 302 does not have to have a frame shape as shown in the figure. For example, the support substrate 302 may have only a rectangular part connected to the base part of the elastic beam 304.

As described above, the drive actuator includes an exciting coil and a permanent magnet provided opposite to each other, and can be configured to swing the oscillator by an electromagnetic force generated by a modulation current applied to the excitation coil. The configuration described is also possible.

In one embodiment, the drive actuator includes drive electrodes provided opposite to each other, and can be configured to rock the rocking body with an electrostatic force generated by a modulation voltage applied to the drive electrode. FIG. 6 is a cross-sectional view showing this configuration. In FIG. 6, 202 is a support part, 204 is a rocking body supported to be rockable with respect to the support part 202, 205 is a rocking shaft of the rocking body 204, 207 is a spacer, and 212 is a drive on the rocking body 204. Electrode. The drive electrode 212 is grounded, for example. Reference numeral 208 denotes a lower support substrate, 221 denotes an upper support substrate, and 210 and 211 denote drive electrodes on the lower support substrate 208. By alternately applying a voltage to the drive electrodes 210 and 211, an attractive force acts alternately between the drive electrode 212 and the drive electrode 210 and between the drive electrode 212 and the drive electrode 211, and the oscillator 204 moves around the oscillation axis 205. It can be swung.

In another embodiment, the driving actuator includes a piezoelectric element, and can be configured to swing the oscillator with vibration energy generated by a modulation voltage applied to the piezoelectric element. The piezoelectric element is provided in a support portion that supports the swinging body so as to be swingable.

Further, as described above, the position adjusting actuator includes a correction coil and a permanent magnet that are provided to face each other, and can be configured to adjust the neutral position of the oscillating body by an electromagnetic force generated by a direct current applied to the correction coil. However, the following configuration is also possible.

In one embodiment, the position adjusting actuator can include a correction electrode provided oppositely, and can be configured to adjust the neutral position of the oscillator with an electrostatic force generated by a DC voltage applied to the correction electrode. FIG. 6 is a cross-sectional view showing this configuration example. In FIG. 6, 222 is a correction electrode on the upper support substrate 221, and 224 is a correction electrode on the oscillator 204. The electrode 224 is grounded, for example. By applying a DC voltage to the correction electrode 222, an attractive force acts between the correction electrode 222 and the correction electrode 224, and the neutral position of the oscillator 204 is adjusted and corrected. When the oscillator 204 is formed of conductive silicon or the like, the correction electrode 224 can be omitted. When the oscillator device configured as shown in FIG. 6 is used in an optical scanner, for example, if an actuator for driving and position adjustment is provided in the portion of the driver shown in FIG. 7 and FIG. Input / output is not hindered.

The oscillator device can also be configured as follows. That is, it has an oscillating body supported so as to be able to oscillate around the oscillating shaft across the neutral position, and an electromagnetic actuator for oscillating the oscillating body around the oscillating shaft. Including a coil and a permanent magnet. Then, by applying a current obtained by superimposing a modulation current and a direct current from a common or separate power source to the coil, the neutral position of the oscillating body is adjusted and the oscillating body is oscillated. In this case, it is not necessary to provide two sets of electromagnetic actuators for driving and for position adjustment.

The combination of the form of the drive actuator and the form of the position adjusting actuator is free as far as it is possible in terms of configuration. Of course, both can be electromagnetic or electrostatic, or the drive actuator can be electromagnetic or piezoelectric and the position adjustment actuator can be electrostatic. The driving actuator may be electrostatic or piezoelectric, and the position adjusting actuator may be electromagnetic. As described above, the oscillating body is typically configured to be capable of resonant vibration, but can be intentionally oscillated at a frequency other than the resonant frequency.

The oscillator device can be used in various devices. As will be described in an embodiment to be described later, an optical deflecting element that deflects and scans a light beam can be provided on an oscillating body and used in an optical scanner. Here, the accuracy of the position where the light beam strikes can be improved.

In addition, a detection electrode that induces induced charges corresponding to the potential of the potential measurement target may be provided on the oscillator that is disposed to face the potential measurement target, and used for the potential sensor. An example of this is shown in the sectional view of FIG. In FIG. 5, a measurement target surface 151 is, for example, a photosensitive drum, and rotates about an axis extending in the left-right direction in the drawing or an axis extending in a direction perpendicular to the paper surface. When the surface 151 to be measured facing the oscillating body 104 is substantially planar, the oscillating body 104 is disposed so as to be substantially parallel to the surface in the neutral position. Reference numeral 152 denotes a case for accommodating the potential sensor, which is formed of a conductive material and is grounded to the ground. The support substrate 100 that supports the oscillator 104 is fixed to the case 152 by appropriate mounting jigs 153 and 154. Due to the presence of this case 152, the electric lines of force reach the detection electrodes 111 and 112 only from the portion of the measurement target surface 151 that faces the oscillator 104 almost directly in front. As a result, the noise component can be suppressed and the potential can be measured with high accuracy. Here, the oscillator 104 is oscillated around the neutral position with the central axis C of the torsion spring as the oscillation center by the driving actuator composed of the permanent magnet 113 and the exciting coil at the portion indicated by reference numeral 114. With this oscillating motion, the distance between the detection electrodes 111 and 112 and the measurement target surface 151 changes periodically with a phase shift of 180 degrees. Accordingly, the phase is shifted by 180 degrees to the detection electrodes 111 and 112, and the induced charges are periodically induced. Therefore, the potential of the measurement target surface 151 is measured by differentially amplifying the signals related thereto. be able to. At this time, since the neutral position of the oscillating body 104 can be adjusted and corrected by the position adjusting actuator, more accurate potential measurement can be performed. Here, the position adjusting actuator is composed of a permanent magnet 113 and a correction coil in a portion indicated by reference numeral 114.

Next, an embodiment of the present invention will be described with reference to the drawings.

(Example 1)
FIG. 1 is a conceptual configuration diagram illustrating an optical scanner according to Embodiment 1 of the present invention. In the configuration of this optical scanner, an oscillating body 1 with a reflecting mirror 10 is provided so as to oscillate around a support beam 2. In addition to the exciting coil 5 that constitutes a drive actuator that drives the oscillator 1, a correction coil 7 that constitutes a position adjusting actuator is disposed in the vicinity of the oscillator 1. A direct current is supplied from the correction DC power source 8 to the correction coil 7 of the position adjusting actuator. An alternating current is passed from the exciting alternating current power source 6 to the exciting coil 5 of the driving actuator, and the rocking body 1 is swung around the support beam 2. The oscillating body 1 is also provided with a permanent magnet 4 that constitutes a driving actuator and a position adjusting actuator, respectively. The excitation coil 5 and the correction coil 7 are overlapped as shown in the figure, and the core 9 is provided at the center thereof.

An offset magnetic field, which is a static magnetic field generated from the correction coil 7 of the actuator for position adjustment, is combined with an alternating magnetic field generated from the excitation coil 5 of the actuator for driving the oscillator, and acts on the permanent magnet 4 on the oscillator 1. As a result, the support beam 2 is bent, the neutral position of the oscillator 1 with the mirror 10 is adjusted and corrected, and an external force for resonance vibration is applied to the oscillator 1.

FIG. 2 shows a structure in a cross section viewed from a direction parallel to the extending direction of the reflecting mirror 10 and the support beam 2. As can be seen, the magnet 4 is installed on the back surface opposite to the surface on which the reflecting mirror 10 is provided, and the polarity of the magnet 4 is set in accordance with the vibration direction of the oscillating body 1 with the mirror 10. Here, the extension direction of the magnet 4 is perpendicular to the extension direction of the beam 2.

In the above configuration, first, a static magnetic field is generated by flowing a correction DC current through the correction coil 7, and a force is applied in the direction of attracting the magnet 4. As a result, the oscillating body 1 with the mirror 10 moves in the direction of rotation and the direction perpendicular to the mirror reflecting surface, and the neutral position is adjusted. In this way, the direction in which the light beam incident on the mirror 10 is reflected can be adjusted. If the oscillator 1 is driven by the exciting AC power source 6 after adjusting the neutral position, the light beam is scanned around the optical axis that is the reflection direction at the neutral position after adjustment.

According to the optical scanner of the present embodiment, since the neutral position of the oscillator 1 can be adjusted, it is possible to improve the accuracy of the position where the scanned light beam strikes. In addition, since the neutral position of the oscillator 1 can be readjusted at any time after the device is installed, high-precision optical scanning can be maintained even if a general material is used for the material of the device. Down is possible.

As shown in FIG. 3, the correction coil is composed of the two portions 18 and 19, and the winding is wound in the shape of figure 8, so that the movement adjustment in the rotational direction of the oscillator 1 can be canceled. Further, the oscillating body 1 can be pulled or moved away in the direction perpendicular to the mirror reflection surface depending on the direction of the direct current flowing through the correction coils 18 and 19. Thus, the neutral position can be adjusted with higher accuracy. FIG. 3 is a view of the coil as viewed from above. Here, the exciting coil 5 is provided with a core 9, and the correction coils 18 and 19 are coils having an air core 20.

(Example 2)
Example 2 will be described. In the second embodiment, as shown in FIG. 4, the correction coil is omitted, and only the exciting coil 25 around the core 29 can obtain the same operation and effect as the above-described embodiment. In the configuration shown in FIG. 4, a superimposed current obtained by adding the excitation AC from the excitation AC power supply 26 and the correction DC from the correction DC power supply 28 by the addition circuit 27 flows to the excitation coil 25. The neutral position of the oscillating body 1 with the reflecting mirror 10 is slightly moved and adjusted by the correction direct current, and the optical axis that is the reflection direction of the reflected light beam at the neutral position is adjusted. Then, after adjustment, the exciting body with the reflection mirror 10 can be caused to resonate by flowing an exciting alternating current, and the light beam can be scanned across the optical axis. Here, the thermal influence can be reduced by reducing the direct current with respect to the amplitude of the alternating current.

The oscillator device according to the present invention can be used for an apparatus that needs to accurately scan a light beam with an optical scanner, such as an image reader, OCR, barcode reader, or LBP. Furthermore, as described above, it can also be used in devices such as a potential sensor that preferably adjust and correct the neutral position of the oscillator.

1 is a conceptual configuration diagram showing an optical scanner according to Embodiment 1 of the present invention. 1 is a cross-sectional view illustrating an optical scanner according to Example 1. FIG. 6 is a top view for explaining a modified example of Embodiment 1. FIG. FIG. 5 is a conceptual configuration diagram illustrating an optical scanner according to Embodiment 2 of the present invention. It is sectional drawing explaining the structural example of the electric potential sensor using the oscillator device by this invention. It is sectional drawing explaining the other structural example of the oscillator device by this invention. It is a top view which shows the form example containing the some rocking body of the rocking body apparatus by this invention. It is a top view which shows the other example of a form containing the some rocking body of the rocking body apparatus by this invention.

Explanation of symbols

1, 104, 204, 301, 301a Oscillator
2, 205, 300 Oscillating shaft (support beam)
4, 113 Drive means, position adjustment means (drive actuator, position adjustment actuator, permanent magnet)
5, 25, 114 Drive means (drive actuator, excitation coil)
6, 26 Drive means (drive actuator, excitation AC power supply)
7, 18, 19, 25, 114 Position adjustment means (position adjustment actuator, correction coil)
8, 28 Position adjustment means (position adjustment actuator, correction DC power supply)
10 Light deflection element (reflection mirror)
111, 112 sensing electrode
151 Potential measurement target (surface to be measured)
210, 211, 212 Drive electrode
222, 224 Correction electrode

Claims (10)

An oscillating body supported so as to be able to oscillate around an oscillating shaft across a neutral position;
Drive means for swinging the swing body about the swing shaft;
Position adjusting means for adjusting a neutral position of the rocking body;
An oscillator device characterized by comprising: 2. The oscillating body according to claim 1, wherein the driving means includes an exciting coil and a permanent magnet provided to face each other, and the oscillating body is oscillated by an electromagnetic force generated by a modulation current applied to the exciting coil. apparatus. 2. The oscillating body device according to claim 1, wherein the driving means includes driving electrodes provided to face each other, and the oscillating body is oscillated by an electrostatic force generated by a modulation voltage applied to the driving electrode. 2. The oscillator device according to claim 1, wherein the driving means includes a piezoelectric element and causes the oscillator to swing with vibration energy generated by a modulation voltage applied to the piezoelectric element. 2. The position adjusting means includes a correction coil and a permanent magnet provided to face each other, and adjusts the neutral position of the oscillating body by an electromagnetic force generated by a direct current applied to the correction coil. 5. The oscillator device according to any one of 4 above. 5. The position adjustment means includes a correction electrode provided oppositely, and adjusts the neutral position of the oscillator with an electrostatic force generated by a DC voltage applied to the correction electrode. 2. The oscillator device according to claim 1. An oscillating body supported so as to be able to oscillate around an oscillating shaft across a neutral position;
An actuator for swinging the swing body about the swing shaft;
Have
The actuator includes a coil and a permanent magnet provided to face each other,
By applying a current in which a modulation current and a direct current are superimposed on the coil, the neutral position of the oscillating body is adjusted and the oscillating body is oscillated.
An oscillator device characterized by the above. 8. The oscillator device according to claim 1, wherein the oscillator is configured to be capable of resonant oscillation. Including the oscillator device according to any one of claims 1 to 8,
The oscillator is provided with an optical deflection element that deflects and scans a light beam.
An optical scanner characterized by that. Including the oscillator device according to any one of claims 1 to 8,
A sensing electrode for inducing induced charges according to the potential of the potential measurement object is provided on the oscillator arranged to face the potential measurement object.
A potential sensor characterized by that.

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