JP2021162706A - Mirror device - Google Patents

Abstract

To provide a mirror device that can oscillate a mirror member at a desired resonance frequency regardless of a change in environmental temperature.SOLUTION: A mirror device according to the present invention has: a mirror body that can oscillate around one axis, has a reflection surface formed on one face, is provided with a first permanent magnet at the center of the other face, and is provided with a pair of second permanent magnets arranged across the one axis on the other face; a driving part that is arranged in an area on the other face of the mirror body and includes a first yoke having a pair of end parts opposite across the first permanent magnet; and an adjustment part that is arranged in the area on the other face of the mirror body and includes a pair of second yokes each having an end part opposite to each of the pair of second permanent magnets.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mirror device that swings a mirror having a reflecting surface.

There is known a scanning device that obtains various information about an object located in the predetermined region by emitting light toward a predetermined region while deflecting the light and detecting the light returned from the predetermined region. There is.

As such a scanning device, a torsion bar is twisted by applying an external force to a movable mirror member such as a MEMS (Micro Electro Mechanical System) mirror that deflects light by magnetic force or the like to reciprocate the mirror as a rotation axis. Has been proposed (see, for example, Patent Document 1). In such an optical scanning device, the mirror member swings at a resonance frequency determined by the moment of inertia of the mirror member and the spring constant of the torsion bar.

By the way, since the spring constant of the torsion bar changes with temperature, the resonance frequency of the mirror member also changes with the temperature change.

Therefore, in the above-mentioned optical scanning device, in order to thermally isolate the mirror member, the mirror member is covered with a cover member.

JP-A-2009-69676

However, when the mirror member is covered with the cover member as described above, the temperature change can be moderated in response to a sudden temperature change in the external environment, but the temperature around the mirror member is substantially constant with the cover member alone. Can't be kept in.

Therefore, even in such an optical scanning device, the resonance frequency of the mirror member changes due to the influence of the temperature change in the external environment.

Therefore, one of the objects of the present invention is to provide a mirror device capable of swinging a mirror member at a desired resonance frequency regardless of a change in environmental temperature.

The invention according to claim 1 is swingable about one axis, has a reflective surface formed on one surface, a first permanent magnet is provided in the center of the other surface, and the other surface. A mirror body provided with a pair of second permanent magnets arranged across the first axis, and a mirror body arranged in a region on the other surface side of the mirror body and facing each other across the first permanent magnet. A drive unit including a first yoke having a pair of end portions and a region on the other side of the mirror body, each facing each of the pair of second permanent magnets. It has an adjusting portion including a pair of second yokes having an end portion.

The invention according to claim 7 is a mirror body in which a reflective surface is formed on one surface, a permanent magnet is provided in the center of the other surface, and the mirror body can swing around one axis, and the other mirror body. A mirror device having a pair of ends that are arranged in a region on the surface side and face each other across the first permanent magnet, and a drive unit that includes a yoke around which a coil is wound. The unit applies a current obtained by superimposing a DC component corresponding to the swing frequency of the mirror body on the alternating current to the coil wound around the yoke.

It is a figure which shows the whole structure of the mirror scanner as the mirror device which concerns on Example 1. FIG. It is a top view of the mirror part. It is a block diagram which shows an example of the internal structure of a mirror drive circuit and a swing frequency adjustment circuit. It is a waveform figure which shows an example of a swing detection signal. It is a figure which shows the positional relationship between a mirror body and each yoke at the time of swinging. It is a figure which shows the other positional relationship between a mirror body and each yoke at the time of swinging. It is a figure for demonstrating the state of each yoke when the resonance frequency of a mirror body is higher than a reference frequency, and the action which exerts on a mirror body. It is another figure for demonstrating the state of each yoke when the resonance frequency of a mirror body is higher than a reference frequency, and the action which exerts on a mirror body. It is a figure for demonstrating the state of each yoke when the resonance frequency of a mirror body becomes less than a reference frequency, and the action which exerts on a mirror body. It is another figure for demonstrating the state of each yoke in the case where the resonance frequency of a mirror body becomes less than a reference frequency, and the action which exerts on a mirror body. It is a figure which shows an example of the whole structure of the mirror scanner as the mirror device which concerns on Example 2. FIG. It is a block diagram which shows another example of the internal structure of a mirror drive circuit.

Preferred embodiments of the present invention will be described in detail below. In the description and the accompanying drawings in each of the following examples, substantially the same or equivalent parts are designated by the same reference numerals.

FIG. 1 is a diagram showing an example of the overall configuration of the mirror scanner 100 according to the first embodiment as a mirror device. The mirror scanner 100 is, for example, a magnetically driven MEMS (Micro Electro Mechanical System) device, which is a plate-shaped mirror portion 10 that performs light deflection and a magnetic field generation source that generates a magnetic field for swinging the mirror portion 10. It has a magnetic circuit 20 and a certain magnetic circuit 20.

FIG. 2 is a plan view of the mirror portion 10 when the mirror portion 10 is viewed from the direction of the white arrow shown in FIG.

As shown in FIG. 2, the mirror unit 10 indicates a mirror body 10S having a light reflecting surface RF, an annular frame body 10W surrounding the mirror body 10S, and the mirror body 10S by a rocking axis AY (dashed line). ) Has a torsion bar 10T that supports it in a swingable state.

Permanent magnets 13, 15a and 15b are fixed to the surface of the mirror body 10S opposite to the light reflecting surface RF, as shown in FIGS. 1 and 2.

The permanent magnet 13 is fixed at a central position on the opposite surface of the light reflecting surface RF in the mirror body 10S.

The permanent magnets 15a and 15b are fixed to each other on the opposite surface of the light reflecting surface RF at positions separated from each other with the permanent magnets 13 interposed therebetween.

In the embodiment shown in FIG. 1, each of the permanent magnets 13, 15a and 15b has an S pole on the surface fixed to the mirror body 10S and an N pole on the opposite surface.

The magnetic circuit 20 includes yokes 21, 31a and 31b made of a soft magnetic material such as an electromagnetic steel plate, a mirror drive circuit 25, and a swing frequency adjusting circuit 26. As shown in FIG. 1, the yokes 21, 31a and 31b are arranged in the magnetic field of the permanent magnets 13, 15a and 15b in the region of the mirror portion 10 on the opposite surface side of the light reflecting surface RF. As shown in FIG. 1, coils 23, 33a and 33b are individually wound around the yokes 21, 31a and 31b, respectively.

The yoke 21 has, for example, a C-shape or a U-shape, and is installed so that a pair of ends thereof sandwich the permanent magnet 13 in a non-contact state as shown in FIG. There is. The yoke 21 functions as an electromagnet that generates an alternating magnetic field from a pair of ends of the yoke 21 when an alternating current flows through a coil 23 wound around the yoke 21.

The yoke 31a has, for example, a rod shape, and one end portion 34a thereof is installed so as to be arranged in a non-contact state with the permanent magnet 15a and at a position facing the permanent magnet 15a as shown in FIG. The yoke 31a functions as an electromagnet that generates an N-pole or S-pole magnetic field from its end 34a when a direct current flows through a coil 33a wound around it. For example, when a negative DC current flows through the coil 33a, an S-pole magnetic field is generated from the end 34a of the yoke 31a, and when a positive DC current flows through the coil 33a, the N-pole from the end 34a of the yoke 31a. A magnetic field is generated.

The yoke 31b has, for example, a rod shape, and one end portion 34b thereof is installed so as to be arranged in a non-contact state with the permanent magnet 15b and at a position facing the permanent magnet 15b as shown in FIG. The yoke 31b functions as an electromagnet that generates an N-pole or S-pole magnetic field from its end 34b when a direct current flows through a coil 33b wound around it. For example, when a negative DC current flows through the coil 33b, an S-pole magnetic field is generated from the end 34b of the yoke 31b, and when a positive DC current flows through the coil 33b, the N-pole from the end 34b of the yoke 31b. A magnetic field is generated.

The mirror drive circuit 25 generates an alternating magnetic field by reversing the polarities of the magnetic fields generated at each of the pair of ends while generating an N-pole magnetic field and an S-pole magnetic field at each of the pair of ends of the yoke 21. generate. At this time, when the alternating magnetic field is applied to the permanent magnet 13, the mirror body 10S resonates around the swing axis AY, and the mirror body 10S swings.

The swing frequency adjusting circuit 26 generates an N-pole magnetic field or an S-pole magnetic field at the ends 34a and 34b of the pair of yokes 31a and 31b, respectively. The swing frequency adjusting circuit 26 generates an attractive force or a repulsive force between the yoke 31a (31b) and the permanent magnet 15a (15b) by the generated magnetic field, so that the swing frequency of the mirror body 10S at the time of swing can be set. adjust.

FIG. 3 is a block diagram showing an example of the internal configuration of the mirror drive circuit 25 and the swing frequency adjustment circuit 26.

As shown in FIG. 3, the mirror drive circuit 25 includes an alternating current source 250. The AC current source 250 generates an AC current for swinging the mirror body 10S around the swing shaft AY, and supplies this to the coil 23 of the yoke 21.

The swing frequency adjusting circuit 26 includes a vibration sensor 252, a control unit 253, and variable DC current sources 254 and 255.

The vibration sensor 252 detects the swing state of the mirror body 10S, and supplies the swing detection signal FD having a signal waveform corresponding to the swing to the control unit 253.

FIG. 4 is a waveform diagram showing an example of the swing detection signal FD.

As shown in FIG. 4, the swing detection signal FD follows the swing of the mirror body 10S, and its signal level periodically changes from the maximum value to the minimum value around the center level Q.

The control unit 253 sets the variable DC current source 254 to the off state during the period when the signal level of the swing detection signal FD is higher than the center level Q shown in FIG. 4, and sets the variable DC current source 254 to the on state during the low period. The on / off signal GON1 is supplied to the variable direct current current source 254. Further, the control unit 253 sets the variable DC current source 255 to the on state during the period when the signal level of the swing detection signal FD is higher than the center level Q, and sets the variable DC current source 255 to the off state during the period when the signal level is lower than the center level Q. Is supplied to the variable DC current source 255.

Further, the control unit 253 measures the frequency at the time of swinging of the mirror body 10S as the swinging frequency based on the swinging detection signal FD. Then, when the measured swing frequency is higher than the predetermined reference frequency, the control unit 253 supplies the variable DC current sources 254 and 255 with a current control signal CR that prompts the generation of, for example, a negative direct current. .. On the other hand, when the measured swing frequency is equal to or lower than the reference frequency, the control unit 253 supplies the variable DC current sources 254 and 255 with a current control signal CR prompting the generation of a positive direct current.

The variable DC current source 254 is turned on while the power on / off signal GON1 is shown to be on, and generates a DC current IG1 having a polarity urged by the current control signal CR, which is connected to the coil 33a of the yoke 31a. Supply. On the other hand, while the power on / off signal GON1 indicates an off state, the variable direct current current source 254 stops the operation of generating the direct current IG1.

The variable DC current source 255 is turned on while the power on / off signal GON2 is in the ON state, generates a DC current IG2 having a polarity promoted by the current control signal CR, and supplies this to the coil 33b of the yoke 31b. do. On the other hand, while the power on / off signal GON2 indicates an off state, the variable direct current current source 255 stops the operation of generating the direct current IG2.

The operation of the mirror scanner 100 shown in FIG. 1 will be described below.

First, the yoke 21 has an N pole at one of its pair of ends and an S pole at the other, and subsequently one at the pair of ends has an S pole and the other, according to the alternating current supplied from the mirror drive circuit 25. Generates an alternating magnetic field in which the state where is N pole is repeated alternately. When the alternating magnetic field is applied to the permanent magnets 13 of the mirror body 10S, attractive and repulsive forces are alternately generated between the pair of ends of the yoke 21 and the permanent magnets 13. As a result, the mirror body 10S swings around the swing shaft AY. At this time, the mirror body 10S resonates at a frequency based on the spring constant of the torsion bar 10T by twisting the torsion bar 10T that supports the mirror body 10S. That is, the mirror body 10S swings around the swing shaft AY at a resonance frequency corresponding to the spring constant of the torsion bar 10T.

5A and 5B are diagrams showing the positional relationship between the mirror body 10S and the yoke 21, the yokes 31a and 31b during rocking.

Note that FIG. 5A shows, for example, the positional relationship between the mirror body 10S and the yokes 21, yokes 31a and 31b at the time when the signal level of the swing detection signal FD shown in FIG. 4 reaches the maximum value. On the other hand, FIG. 5B shows the positional relationship between the mirror body 10S and the yokes 21, yokes 31a and 31b at the time when the signal level of the swing detection signal FD becomes the minimum value, for example.

Here, assuming that the angle of the mirror body 10S when the permanent magnet 13 is not receiving the alternating magnetic field is the base point angle J0, the mirror body 10S is shown in FIGS. 5A and 5B when the permanent magnet 13 receives the alternating magnetic field. As described above, it swings at a swing angle θ with respect to the base point angle J0.

In the state shown in FIG. 5A, the variable DC current source 255 of the variable DC current sources 254 and 255 is turned on. As a result, only the yoke 31b of the yokes 31a and 31b functions as an electromagnet, and a magnetic field is generated from the end 34b of the yoke 31b. At this time, no magnetic field is generated from the end 34a of the yoke 31a.

On the other hand, in the state shown in FIG. 5B, the variable DC current source 254 of the variable DC current sources 254 and 255 is turned on. As a result, only the yoke 31a of the yokes 31a and 31b functions as an electromagnet, and a magnetic field is generated from the end portion 34a of the yoke 31a. At this time, no magnetic field is generated from the end 34b of the yoke 31b.

That is, each of the yokes 31a and 31b functions as an electromagnet when the permanent magnets (15a, 15b) facing themselves are approaching as the mirror body 10S swings.

Here, when the swing frequency of the mirror body 10S based on the swing detection signal FD is higher than the predetermined reference frequency, the variable DC current source 254 (255) sets the negative electrode DC current IG1 (IG2) to the yoke 31a. It is supplied to the coils 33a (33b) of (31b). As a result, the end portion 34a (34b) of the yoke 31a (31b) generates a magnetic field of the S pole, and an attractive force is generated between the yoke 31a (31b) and the permanent magnet 15a (15b).

6A and 6B are diagrams for explaining the states of the yokes 31a and 31b when the swing frequency of the mirror body 10S is higher than a predetermined reference frequency and the action on the mirror body 10S. Note that FIG. 6A shows the positional relationship of the mirror bodies 10S, yoke 21, yokes 31a and 31b similar to those in FIG. 5A, and FIG. 6B shows the mirror bodies 10S, yoke 21, yokes 31a and 31b similar to those in FIG. 5B. Represents the positional relationship of.

When the permanent magnet 15b approaches the end 34b of the yoke 31b as the mirror body 10S swings, a magnetic field of the S pole is generated from the end 34b of the yoke 31b as shown in FIG. 6A. As a result, the yoke 31b generates an attractive force with respect to the permanent magnet 15b that generates the N-pole magnetic field.

On the other hand, when the permanent magnet 15a approaches the end 34a of the yoke 31a as the mirror body 10S swings, a magnetic field of the S pole is generated from the end 34a of the yoke 31a as shown in FIG. 6B. As a result, the yoke 31a generates an attractive force with respect to the permanent magnet 15a that generates the N-pole magnetic field.

That is, when the ambient temperature around the mirror portion 10 becomes low, the spring constant of the torsion bar 10T becomes large, and the resonance frequency of the mirror body 10S fluctuates in the direction of increasing.

Therefore, in such a case, a magnetic field that generates an attractive force with respect to the permanent magnets 15a (15b) is generated in the yoke 31a (31b). At this time, as the swing angle of the mirror body 10S becomes larger, the distance between the yoke 31a (31b) and the permanent magnets 15a (15b) becomes narrower, and the attractive force becomes stronger. As a result, the apparent spring constant of the torsion bar 10T supporting the mirror body 10S becomes small, and the resonance frequency of the mirror body 10S decreases.

Therefore, according to such an operation, it is possible to suppress an increase in the resonance frequency of the mirror body 10S due to a decrease in the environmental temperature.

On the other hand, when the resonance frequency of the mirror body 10S based on the swing detection signal FD is equal to or lower than a predetermined reference frequency, the variable DC current source 254 (255) sets the negative DC current IG1 (IG2) to the yoke 31a ( It is supplied to the coils 33a (33b) of 31b). As a result, the end portion 34a (34b) of the yoke 31a (31b) generates an N-pole magnetic field, and a repulsive force is generated between the yoke 31a (31b) and the permanent magnet 15a (15b).

7A and 7B are diagrams for explaining the states of the yokes 31a and 31b when the resonance frequency of the mirror body 10S is equal to or lower than a predetermined reference frequency, and the action on the mirror body 10S. 7A shows the positional relationship of the mirror bodies 10S, yoke 21, yokes 31a and 31b similar to those in FIG. 5A, and FIG. 7B shows the mirror bodies 10S, yoke 21, yokes 31a and 31b similar to those in FIG. 5B. Represents the positional relationship of.

As shown in FIG. 7A, when the permanent magnet 15b approaches the end 34b of the yoke 31b as the mirror body 10S swings, an N-pole magnetic field is generated from the end 34b of the yoke 31b. As a result, the yoke 31b generates a repulsive force with respect to the permanent magnet 15b that generates the N-pole magnetic field.

On the other hand, as shown in FIG. 7B, when the permanent magnet 15a approaches the end 34a of the yoke 31a as the mirror body 10S swings, an N-pole magnetic field is generated from the end 34a of the yoke 31a. As a result, the yoke 31a generates a repulsive force with respect to the permanent magnet 15a that generates the N-pole magnetic field.

That is, when the ambient temperature around the mirror portion 10 becomes high, the spring constant of the torsion bar 10T becomes small, and the resonance frequency of the mirror body 10S fluctuates in the direction of becoming low.

Therefore, in such a case, a magnetic field that generates a repulsive force with respect to the permanent magnets 15a (15b) is generated in the yoke 31a (31b). At this time, as the swing angle of the mirror body 10S becomes larger, the distance between the yoke 31a (31b) and the permanent magnets 15a (15b) becomes narrower, and the repulsive force becomes stronger. As a result, the apparent spring constant of the torsion bar 10T supporting the mirror body 10S increases, and the resonance frequency of the mirror body 10S increases.

Therefore, according to such an operation, it is possible to suppress a decrease in the resonance frequency of the mirror body 10S due to an increase in the environmental temperature.

As described in detail above, in the mirror scanner 100, the resonance frequency of the mirror body 10S is formed by the adjusting unit including the swing frequency adjusting circuit 26, the yokes 31a and 31b, and the permanent magnets 15a and 15b fixed to the mirror body 10S. Is adjustable.

Therefore, according to the mirror scanner 100, it is possible to maintain the resonance frequency of the mirror body 10S at a desired reference frequency regardless of changes in the environmental temperature.

In the above embodiment, the surfaces of the permanent magnets 15a and 15b facing the ends 34a and 34b of the yokes 31a and 31b are both N poles, but they may be S poles, or one is S pole and the other is N pole. It may be a pole. At this time, the polarity of the magnetic field generated in the ends 34a and 34b of the yokes 31a and 31b is controlled in accordance with the polarities of the surfaces of the permanent magnets 15a and 15b facing the ends 34a and 34b of the yokes 31a and 31b. do it.

Further, in the above embodiment, the polarities of the magnetic fields generated at the ends 34a and 34b of the yokes 31a and 31b are switched based on the swing frequency of the mirror body 10S. However, when the mirror scanner 100 is used in an environment with little temperature fluctuation, the polarity of the magnetic field generated at the ends 34a and 34b of the yokes 31a and 31b, respectively, is set to one of the north pole and the south pole based on the ambient temperature. It may be fixed to.

Further, in the above embodiment, one of the variable DC current sources 254 and 255 is set to the operating state and the other is set to the stopped state, as shown in FIGS. 6A and 6B, for example, by following the swing of the mirror body 10S. However, the variable DC current sources 254 and 255 may be kept in operation at all times.

In short, the mirror scanner 100 may include the following mirror body, drive unit, and adjustment unit. That is, the mirror body (10S) can swing around one axis (AY), a reflecting surface (RF) is formed on one surface, and a first permanent magnet (13) is formed in the center of the other surface. Is provided, and a pair of second permanent magnets (15a, 15b) arranged with the above-mentioned one axis interposed therebetween are provided on the other surface. The drive unit (21, 23, 25) is a first yoke (21, 23, 25) having a pair of ends arranged in a region on the other surface side of the mirror body and facing each other with the first permanent magnet (13) in between. 21). The adjusting portions (26, 31a, 31b, 33a, 33b) are arranged in the other surface side region of the mirror body, and the ends each facing each of the pair of second permanent magnets (15a, 15b). Includes a pair of second yokes (31a, 31b) having portions (34a, 34b).

FIG. 8 is a diagram showing an example of the overall configuration of the mirror scanner 100A, which is the second embodiment as the mirror device according to the present embodiment.

The mirror scanner 100A employs a mirror portion 10 in which the permanent magnets 15a and 15b shown in FIG. 1 are omitted, and the magnetic circuit 20 omits the swing frequency adjusting circuit 26, yokes 31a and 31b shown in FIG. , The mirror drive circuit 25A is adopted instead of the mirror drive circuit 25.

FIG. 9 is a block diagram showing an example of the internal configuration of the mirror drive circuit 25A.

In FIG. 9, the vibration sensor 252 detects the swing state of the mirror body 10S, and supplies the swing detection signal FD having the signal waveform as shown in FIG. 4 corresponding to the swing to the control unit 253A.

The control unit 253A measures the resonance frequency of the mirror body 10S at the time of swing as the swing frequency based on the swing detection signal FD. Then, the control unit 253A obtains the amount of DC offset current superimposed on the AC current supplied to the coil 23 based on the swing frequency, and supplies the offset signal DCO indicating the offset current amount to the AC current source 250A. For example, the control unit 253A supplies an offset signal DCO indicating a larger DC offset current to the AC current source 250A as the measured resonance frequency becomes higher.

The alternating current source 250A generates an alternating current for swinging the mirror body 10S around the swing shaft AY shown in FIG. The AC current source 250A supplies the coil 23 of the yoke 21 with an offset superimposed AC current in which a DC offset current having an offset current amount indicated by the offset signal DCO is superimposed on the AC current generated as described above.

The yoke 21 generates an alternating magnetic field from its pair of ends when the offset superimposed alternating current flows through the coil 23. As a result, attractive and repulsive forces are alternately generated between the pair of ends of the yoke 21 and the permanent magnets 13, and the mirror body 10S swings around the swing shaft AY. At this time, the mirror body 10S resonates at a frequency based on the spring constant of the torsion bar 10T by twisting the torsion bar 10T that supports the mirror body 10S. That is, the mirror body 10S swings in the circumferential direction of the swing shaft AY at a resonance frequency corresponding to the spring constant of the torsion bar 10T.

Here, when the environmental temperature changes, the spring constant of the torsion bar 10T changes and the resonance frequency of the mirror body 10S fluctuates.

However, in the mirror scanner 100A, even if the resonance frequency of the mirror body 10S fluctuates due to a change in the environmental temperature, the offset current corresponding to the resonance frequency is superimposed on the alternating current that swings the mirror body 10S. As a result, fluctuations in the resonance frequency are suppressed.

Therefore, according to the mirror scanner 100A, it is possible to maintain the resonance frequency of the mirror body 10S at a predetermined reference frequency regardless of changes in the environmental temperature.

In the above embodiment, the DC current corresponding to the measured swing frequency of the mirror body 10S is superimposed on the AC current as an offset current, but the offset that follows the phase of the swing detection signal FD and is superimposed. The amount of current may be changed. For example, at the time points of the maximum value and the minimum value of the swing detection signal FD as shown in FIG. 4, the amount of the superimposed offset current is maximized, and the amount of the current is gradually reduced toward the center level Q.

In short, the mirror scanner 100A may include the following mirror body and drive unit. That is, the mirror body (10S) is in a state in which a reflective surface (RF) is formed on one surface, a permanent magnet (13) is provided in the center of the other surface, and the mirror body (10S) can swing around one axis (AY). It is installed in. The drive unit (25A) is arranged in a region on the other surface side of the mirror body, has a pair of end portions facing each other with the permanent magnet in between, and is wound with a coil (23). A current including (21) in which a direct current component corresponding to the resonance frequency due to the swing of the mirror body is superimposed on the alternating current is applied to the coil wound around the yoke.

10 Mirror unit 10S Mirror body 13, 15a, 15b Permanent magnet 21, 31a, 31b York 23, 33a, 33b Coil 25 Mirror drive circuit 26 Vibration frequency adjustment circuit 100 Mirror scanner 250 AC current source 252 Vibration sensor 253 Control unit 254, 255 variable DC power supply

Claims (7)

It is swingable around one axis, a reflective surface is formed on one surface, a first permanent magnet is provided in the center of the other surface, and the other surface is arranged with the axis 1 in between. A mirror body provided with a pair of second permanent magnets
A drive unit including a first yoke arranged in a region on the other surface side of the mirror body and having a pair of ends facing each other across the first permanent magnet.
Having an adjusting portion that includes a pair of second yokes that are located in the other face-side region of the mirror body and each has an end facing each of the pair of second permanent magnets. A mirror device characterized by. The driving unit reverses the polarity of the magnetic field generated at each of the pair of ends while generating an N-pole magnetic field and an S-pole magnetic field at the pair of ends of the first yoke, respectively. The mirror body is resonated around the axis of 1 to swing the mirror body.
The adjusting unit generates an N-pole magnetic field or an S-pole magnetic field at the ends of each of the pair of second yokes, and the generated magnetic field causes the pair of second yokes and the pair of second permanent magnets. The mirror device according to claim 1, wherein the swing frequency of the mirror body at the time of swing is adjusted by generating an attractive force or a repulsive force with the magnet. The adjusting unit includes a sensor that detects a swing state of the mirror body and generates a swing detection signal having a signal waveform corresponding to the swing.
When the swing frequency of the mirror body based on the swing detection signal is higher than a predetermined reference frequency, an attractive force is generated between the pair of second yokes and the pair of second permanent magnets, and the above-mentioned When the swing frequency is equal to or lower than the reference frequency, the pair of second yokes are said to generate a repulsive force between the pair of second yokes and the pair of second permanent magnets. The mirror device according to claim 2, wherein an N-pole magnetic field or an S-pole magnetic field is generated at an end portion. When one of the pair of second permanent magnets approaches one of the pair of second yokes as the mirror body swings, the adjusting unit receives the pair of second permanent magnets. When the magnetic field generation in the second yoke of the other of the yokes is stopped and the other of the pair of second permanent magnets approaches the second yoke of the other, the second of the one is said. The mirror device according to claim 2 or 3, wherein the generation of a magnetic field in the yoke of the above is stopped. A coil is individually wound around each of the first yoke and the pair of second yokes.
The drive includes an alternating current source that applies an alternating current to the coil wound around the first yoke.
2. The mirror device according to 1. When the swing frequency is higher than the reference frequency, the adjusting unit supplies a first direct current as the direct current to the coils wound around each of the pair of second yokes, while the swinging unit. When the dynamic frequency is equal to or lower than the reference frequency, a second direct current having a polarity different from that of the first direct current is supplied to the coil wound around each of the pair of second yokes as the direct current. The mirror device according to claim 5, wherein the first and second direct current sources are controlled so as to cause the first and second direct current sources to be controlled. A mirror body in which a reflective surface is formed on one surface, a permanent magnet is provided in the center of the other surface, and the mirror body can swing around one axis.
A mirror device having a pair of end portions arranged in a region on the other surface side of the mirror body and facing each other across the first permanent magnet, and a drive portion including a yoke in which a coil is wound. And
The drive unit is a mirror device, characterized in that a current obtained by superimposing a DC component corresponding to a swing frequency at the time of swing of the mirror body on an alternating current is applied to the coil wound around the yoke.

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