JP2006189497A - Reflecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To providing a reflecting device for improving lightweight and use efficiency of incident light by highly accurately a tilt angle of a movable plate having a reflection face, enlarging the tilt angle, and facilitating manufacture. <P>SOLUTION: The reflecting device comprises a mirror part 1 having a 2mm square for example, a fixing part 2 for fixing one end face of the mirror part 1, a drive part 3 for driving the mirror part 1, a drive circuit 4 for controlling the drive part 3 and and a memory 5. The mirror part 1 has a reflection face for reflecting light from a light source. The drive part 3 is provided with prescribed spacing to the other end face of the mirror part 1. The drive circuit 4 applies a voltage on an electrode of any one layer or two layers and more out of a plurality of electrodes 3a-3e of the drive part 3 so that the mirror part 1 is tilted at a desired tilt angle to a YZ plane. The memory 5 stores a relationship of a plurality of the tilt angles of the mirror part 1 and one or the plurality of the electrodes of the drive part 3 for applying the voltage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reflection device that reflects light from a light source in a desired direction.

  Conventionally, a liquid crystal panel has been often used as a light valve of a projector.

  In recent years, DMD (digital / digital display) that displays images by arranging micro mirror elements (micro mirrors) on a plane corresponding to pixels and mechanically controlling the angle of each mirror surface using micromachining technology. Mirror device) has been put into practical use.

  Such a DMD has an advantage that a response speed is faster than that of a liquid crystal panel and a bright image can be obtained. Therefore, the DMD is suitable for realizing a small projector having high brightness and high image quality.

  In such a projector, whether or not an image is projected is controlled by a DMD micromirror that repeatedly changes the reflection direction of light.

  On the other hand, for example, when a micromirror is used in a laser printer, it is necessary to scan light from a light source by the micromirror. In other words, by scanning the light from the light source on the photosensitive drum using the micromirror, the photosensitive member on the photosensitive drum is exposed and an image is formed on the photosensitive drum.

  As used in the above laser printer, the method of scanning light from a light source using a micromirror is currently applied to, for example, televisions, in-vehicle head-up displays, in-vehicle laser radars, etc., and researched and developed in various fields. Is being promoted.

  When scanning light from a light source using a micromirror, the micromirror serving as a light reflecting surface is tilted. In this case, driving means for driving the micromirror and detection means for detecting the tilt angle (tilt angle of the micromirror) are required. By feeding back the tilt angle detected by the detection means to the drive means, the micromirror is driven so that the drive means can obtain a desired tilt angle. Hereinafter, examples of various optical devices provided with the driving unit and the detecting unit will be described.

  For example, in the optical device described in Patent Document 1, a movable electrode is provided on an end surface of a movable piece serving as a mirror, and a fixed electrode is provided on an end surface of a fixed plate facing the end surface of the movable piece. The movable state of the movable piece is detected by detecting the electrostatic capacitance generated between the movable electrode and the fixed electrode.

  Further, in the optical scanner described in Patent Document 2, a driving coil is provided on a movable plate having a reflecting mirror formed on one surface, and a current flowing in the driving coil and a magnetic field generated by a permanent magnet provided near the movable plate. The movable plate is deflected by the Lorentz force. The deflection angle of the movable plate is detected based on the induced electromotive force at both ends of the drive coil.

  Further, in the optical deflector described in Patent Document 3, as in Patent Document 2, a driving coil is provided on a movable plate having a reflecting mirror formed on one surface, and the current flowing through the driving coil is near the movable plate. The movable plate performs a deflection motion by the Lorentz force with the magnetic field generated by the provided permanent magnet. The deflection angle of the movable plate is detected based on the voltage of the Hall element provided on the movable plate.

Furthermore, in the optical device described in Patent Document 4, light is incident on a penetrating portion of a movable plate having a reflecting surface, and the deflection angle of the movable plate is detected based on the amount of transmitted light that has passed through the penetrating portion. .
JP-A-6-123845 JP-A-11-305162 JP 2000-81589 A JP 2003-5124 A

  However, in the optical device described in Patent Document 1, the capacitance is detected based on the opposed area between the movable electrode and the fixed electrode. Therefore, it becomes difficult to detect the tilt angle of the movable piece based on the capacitance. Therefore, the movable piece cannot be inclined greatly.

  Further, in the optical scanner and the optical deflector described in Patent Documents 2 and 3, respectively, since the driving coil or the Hall element is provided on the movable plate, the movable plate becomes heavy and the movable plate can be driven at high speed. It becomes difficult and manufacture becomes difficult.

  Furthermore, in the optical device described in Patent Document 4, most of the incident light from the light source is deflected by the reflecting surface of the movable plate, but a part of the incident light is transmitted through the penetrating portion. It penetrates to the back side. As a result, the utilization rate of incident light is significantly reduced.

  It is an object of the present invention to control the inclination angle of a movable plate having a reflecting surface with high accuracy and to increase the inclination angle, making it easy to manufacture, reducing the weight and improving the utilization rate of incident light. Is to provide a simple reflection device.

  A reflecting device according to a first aspect of the present invention is a movable plate having a reflecting surface that reflects light, a fixed portion that supports the movable plate so as to be tiltable, and at least one drive disposed so as to face an end surface of the movable plate. And a control circuit that controls the drive unit, the drive unit includes a plurality of stacked electrodes, an insulating layer is interposed between the plurality of electrodes, and the control circuit includes a plurality of drive units By selectively applying a voltage to at least one of the electrodes, an electrostatic force is generated between the electrode to which the voltage is applied and the end face of the movable plate.

  In the reflecting device according to the present invention, the movable plate is supported by the fixed portion so as to be tiltable. In addition, at least one drive unit is arranged to face the end surface of the movable plate.

  When a voltage is selectively applied to at least one of the plurality of electrodes of the driving unit by the control circuit, an electrostatic force is generated between the electrode to which the voltage is applied and the end surface of the movable plate, and the movable plate is Attracted to the electrode. Thereby, the movable plate can be inclined to a desired inclination angle.

  Thus, by applying a voltage to at least one electrode of the plurality of electrodes of the drive unit by the control circuit, the tilt angle of the movable plate can be controlled with high accuracy and the tilt angle can be increased or decreased.

  Moreover, since the drive part which inclines a movable plate does not exist on a movable plate, manufacture can be simplified and weight reduction of a movable plate can be achieved. Furthermore, light can be reflected and scanned using the entire movable plate as a reflecting surface. Thereby, the utilization factor of light can be improved.

  A reflecting device according to a second aspect of the invention includes a movable plate having a reflecting surface that reflects light, a fixed portion that supports the movable plate so as to be tiltable, and first and first plates disposed so as to face the end surface of the movable plate. The first driving unit includes a plurality of stacked first electrodes, and the second driving unit includes a plurality of stacked first electrodes. Each of the two electrodes, an insulating layer is interposed between the plurality of first and second electrodes, and the control circuit is connected to at least one of the plurality of first electrodes of the first driving unit. A voltage is selectively applied, and a voltage is selectively applied to at least one of the plurality of second electrodes of the second drive unit, whereby the first and second voltages are applied. An electrostatic force is generated between the electrode and the end face of the movable plate.

  In the reflecting device according to the present invention, the movable plate is supported by the fixed portion so as to be tiltable. Further, the first and second driving units are arranged so as to face the end face of the movable plate.

  A voltage is selectively applied to at least one of the plurality of first electrodes of the first driving unit by the control circuit, and at least one of the plurality of second electrodes of the second driving unit. When a voltage is selectively applied to the first and second electrodes, an electrostatic force is generated between the first and second electrodes to which the voltage is applied and the end face of the movable plate, and the movable plate is attracted to the electrode. Thereby, the movable plate can be inclined to a desired inclination angle.

  In this case, when a voltage is applied to the electrodes having different heights of the first drive unit and the second drive unit by the control circuit, the movable plate can be tilted two-dimensionally. When a voltage is applied to the electrodes of the same height of the first driving unit and the second driving unit, the movable plate can be tilted one-dimensionally.

  Thus, by applying a voltage to at least one of the plurality of electrodes of the first and second drive units by the control circuit, the tilt angle of the movable plate can be controlled with high accuracy and the tilt angle is increased or Can be small.

  In addition, since the first and second drive units for inclining the movable plate do not exist on the movable plate, it is possible to facilitate manufacture and reduce the weight of the movable plate. Furthermore, light can be reflected and scanned using the entire movable plate as a reflecting surface. Thereby, the utilization factor of light can be improved.

  The control circuit may apply a voltage to two of the plurality of electrodes of the driving unit. In this case, since the end face of the movable plate can be attracted to the position between the two electrodes, it is possible to set an inclination angle approximately in the middle of the inclination angles set when a voltage is applied to each of the two electrodes. it can. Thereby, the resolution of the tilt angle of the movable plate can be doubled by combining with the case where there is one electrode to which a voltage is applied.

  The control circuit may apply a voltage to at least two of the plurality of electrodes of the driving unit in the initial state. In this case, the position of the movable plate can be returned to the preset initial position when the movable plate is in a free state when not driven by the control circuit and when the movable plate moves out of a desired position during an abnormality. it can. Thereby, the position of the movable plate can be specified.

  The control circuit may apply a voltage to at least one of the plurality of first electrodes of the first drive unit and at least one of the plurality of second electrodes of the second drive unit. In this case, since the end face of the movable plate can be attracted to the position between the two electrodes of the first drive unit, the inclination is approximately the middle of the inclination angle set when a voltage is applied to each of the two electrodes. The corner can be set. Accordingly, the resolution of the tilt angle of the movable plate can be doubled by combining with the case where there is one electrode to which a voltage is applied in the first driving unit.

  The control circuit may apply a voltage to at least one of the plurality of second electrodes of the second driving unit and the plurality of first electrodes of the first driving unit. In this case, since the end face of the movable plate can be attracted to the position between the two electrodes of the second driving unit, the inclination is approximately the middle of the inclination angle set when a voltage is applied to each of the two electrodes. The corner can be set. Accordingly, the resolution of the tilt angle of the movable plate can be doubled by combining with the case where there is one electrode to which a voltage is applied in the second driving unit.

  The control circuit applies a voltage to at least two electrodes of the plurality of first electrodes of the first driving unit in an initial state, and applies to at least two electrodes of the plurality of second electrodes of the second driving unit. A voltage may be applied. In this case, the position of the movable plate can be returned to the preset initial position when the movable plate is in a free state when not driven by the control circuit and when the movable plate moves out of a desired position during an abnormality. it can. Thereby, the position of the movable plate can be specified.

  The movable plate may be connected to the fixed portion by one or a plurality of connecting portions. Thereby, the movable plate is easily and smoothly inclined.

  The movable plate is formed of a rectangular parallelepiped having a hollow structure, and the rectangular parallelepiped has an end surface facing the side surface of the drive unit, and the rectangular parallelepiped is maintained so that the end surface is parallel to the side surface of the drive unit as the rectangular parallelepiped is inclined. It may be formed to be deformable.

  As described above, when the movable plate is formed of a rectangular parallelepiped having a hollow structure and the movable plate is inclined by the electrostatic force, the end surface of the movable plate is parallel to the side surface of the drive unit, so that the electrostatic force is generated at the end surface of the movable plate. The area to receive increases. Thereby, the utilization efficiency of electrostatic force is improved. Thereby, power saving of the reflection device can be realized.

  The fixed portion may include a rotation shaft that rotatably supports the movable plate and a fixed support column that rotatably supports the rotation shaft.

  In this case, since the movable plate is rotatably supported by the rotation shaft and the rotation shaft is rotatably supported by the fixed support column, the movable plate can be easily and smoothly inclined.

According to the present invention, it is possible to control the inclination angle of the movable plate with high accuracy and to increase or decrease the inclination angle by applying a voltage to at least one electrode of the plurality of electrodes of the driving unit by the control circuit. it can. Moreover, since the drive part which inclines a movable plate does not exist on a movable plate, manufacture can be simplified and weight reduction of a movable plate can be achieved. Furthermore, since the light can be reflected and scanned by using the entire movable plate as a reflecting surface, it is possible to improve the light utilization rate.

  Hereinafter, a reflection device according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing the configuration of the reflecting device according to the first embodiment.

  As shown in FIG. 1, the reflection device according to the present embodiment includes, for example, a 2 mm square mirror unit 1, a fixing unit 2 that fixes one end surface of the mirror unit 1, a driving unit 3 that drives the mirror unit 1, and a drive A drive circuit 4 for controlling the unit 3 and a memory 5 are provided.

  Here, an axis perpendicular to the plane of the mirror unit 1 fixed by the fixing unit 2 is defined as an X axis, and two axes orthogonal within the plane of the mirror unit 1 are defined as a Y axis and a Z axis.

  The mirror unit 1 has a reflecting surface that reflects light from a light source (not shown). The mirror unit 1 is formed by, for example, laminating a metal layer made of aluminum (Al) or gold (Au) on a substrate made of silicon (Si).

The drive unit 3 has a stacked structure of a plurality of electrodes 3a to 3e having a thickness of 50 μm, for example. Insulating layers 31 made of, for example, silicon oxide (SiO ₂ ) having a thickness of, for example, 20 μm are provided between the electrodes.

  Here, the drive unit 3 is provided at a predetermined interval (for example, 5 μm) with respect to the other end face of the mirror unit 1. In the present embodiment, the height of the mirror unit 1 is set to be substantially the same as the height of the electrode 3c of the drive unit 3. The position of the mirror unit 1 is set as an initial position.

  The drive circuit 4 applies a voltage to one or more of the plurality of electrodes 3a to 3e of the drive unit 3 so that the mirror unit 1 is inclined at a desired tilt angle (tilt angle) with respect to the YZ plane. Apply.

  When a voltage is applied to a predetermined electrode of the drive unit 3 by the drive circuit 4, an electrostatic force is generated between the applied electrode and the mirror unit 1. Thereby, the mirror part 1 inclines around the Z-axis toward the direction of the electrode to which the voltage of the driving part 3 is applied. The tilt angle of the mirror unit 1 at this time is θz. By tilting the mirror unit 1, light from a light source (not shown) can be reflected and scanned one-dimensionally.

  In this way, the reflecting device in which the mirror unit 1 is tilted around one axis (in this example, around the Z axis) is called a one-dimensional mirror.

  The memory 5 stores a relationship between a plurality of tilt angles of the mirror unit 1 and one or a plurality of electrodes (hereinafter abbreviated as application electrodes) of the driving unit 3 that applies a voltage. That is, from the above relationship of the memory 5, the drive circuit 4 can recognize the electrode to which a voltage is applied in order to obtain a desired tilt angle.

  In the present embodiment, the drive circuit 4 applies a voltage to the electrode of the drive unit 3 based on the above relationship that the memory 5 has.

  FIG. 2 is a schematic diagram showing the configuration of the drive circuit 4 of FIG.

  As illustrated in FIG. 2, the drive circuit 4 includes a DC power supply 41 and switching elements 4 a to 4 e.

  The switching elements 4a to 4e are connected between the DC power supply 41 and the electrodes 3a to 3e of the drive unit 3, respectively. With such a configuration, for example, when a voltage is applied to the electrode 3e of the drive unit 3 via the switching element 4e, the mirror unit 1 is inclined toward the electrode 3e. In this case, the tilt angle around the Z-axis of the mirror unit 1 with the initial position as a reference is θz5. In the initial state, the switching elements 4a to 4e are off.

  As will be described in detail later with reference to FIG. 3, the tilt angle of the mirror unit 1 when a voltage is applied to the electrode 3a is θz1, and the tilt angle of the mirror unit 1 when a voltage is applied to the electrode 3b is θz2. The tilt angle of the mirror unit 1 when a voltage is applied to the electrode 3c is θz3, and the tilt angle of the mirror unit 1 when a voltage is applied to the electrode 3d is θz4. In this case, the tilt angle θz3 of the mirror unit 1 is 0 °, the tilt angles θz1 and θz2 are positive angles, and the tilt angles θz4 and θz5 are negative angles.

  A distance L1 between the fixing unit 2 and the driving unit 3 in FIG. 2 is, for example, 2.005 mm. Further, the length D of the drive unit 3 in FIG. 2 is, for example, 0.5 mm and the width is 2 mm.

  Here, the tilt angle θz of the mirror unit 1 can be calculated by a trigonometric function as shown in the following formula (1).

θz = tan ⁻¹ (nt / L1) (1)
In the above formula (1), t is a length obtained by adding the thickness of one electrode of the driving unit 3 to 50 μm and the thickness of one insulating layer 31 to 20 μm, and n is the initial position of the mirror unit 1 The number of electrodes from the electrode 3c to the applied electrode (not including the electrode 3c) is shown. For example, when a voltage is applied to the electrode 3e, n corresponds to 2.

  FIG. 3 is an explanatory diagram showing an example of the relationship between a specific example of the tilt angle θz stored in the memory 5 of FIG. 1 and the application electrode of the drive unit 3.

  First, the case where the application electrode is a single layer will be described. As shown in FIG. 3, when the applied electrode is the electrode 3a, the tilt angle θz1 of the mirror unit 1 is, for example, 4 °. When the application electrode is the electrode 3b, the tilt angle θz2 of the mirror unit 1 is, for example, 2 °.

  When the application electrode is the electrode 3c, the tilt angle θz3 of the mirror unit 1 is, for example, 0 °. When the application electrode is the electrode 3d, the tilt angle θz4 of the mirror unit 1 is, for example, −2 °. When the application electrode is the electrode 3e, the tilt angle θz5 of the mirror unit 1 is, for example, −4 °.

  Next, the case where the application electrode has two layers will be described. As shown in FIG. 3, when the application electrodes are electrodes 3a and 3b, the tilt angle θz of the mirror unit 1 is 3 °, which is an intermediate value between the tilt angle θz1 and the tilt angle θz2. When the application electrodes are the electrodes 3b and 3c, the tilt angle θz of the mirror unit 1 is 1 ° which is an intermediate value between the tilt angle θz2 and the tilt angle θz3.

  When the application electrodes are the electrodes 3c and 3d, the tilt angle θz of the mirror unit 1 is −1 °, which is an intermediate value between the tilt angle θz3 and the tilt angle θz4. When the application electrodes are electrodes 3d and 3e, the tilt angle θz of the mirror unit 1 is −3 °, which is an intermediate value between the tilt angle θz4 and the tilt angle θz5.

  As described above, since the application electrode has two layers, the resolution of the tilt angle can be doubled as compared with the case where the application electrode has one layer.

  FIG. 4 is a schematic diagram illustrating an example of a method of connecting the mirror unit 1 and the fixed unit 2. FIG. 4A is a top view of the mirror unit 1 and the fixed unit 2, and FIG. 4B is a side view of the mirror unit 1 and the fixed unit 2.

  As shown in FIG. 4A, the mirror portion 1 is connected to the fixed portion 2 by a hinge 11 as a flexible connecting member made of, for example, a polysilicon thin film. Thereby, as shown in FIG.4 (b), the mirror part 1 is inclined easily.

(Second Embodiment)
FIG. 5 is a schematic diagram illustrating a configuration of a reflection device according to the second embodiment.

  As shown in FIG. 5, the reflector unit according to the present embodiment is different from the reflector unit according to the first embodiment in the connection method of the mirror unit 1. Details will be described below.

  In the present embodiment, two rotating shafts 6a are rotatably connected to the end surfaces on both sides of the mirror portion 1 along the Z axis. The two rotation shafts 6a are rotatably provided on the two fixed support columns 6, respectively. With such a configuration, the mirror unit 1 can be tilted when a voltage is applied to a predetermined electrode of the drive unit 3 by the drive circuit 4.

(Third embodiment)
FIG. 6 is a schematic diagram illustrating a configuration of a reflecting device according to the third embodiment.

  As shown in FIG. 6, the reflection device according to the present embodiment is different from the reflection device according to the first embodiment in that the shape of the mirror unit 1 is different and the configuration similar to that of the drive unit 3. The driving unit 7 has a driving circuit 8 that performs the same operation as the driving unit 7 and the driving circuit 4 and applies a voltage to each electrode of the driving unit 7. Details will be described below.

  In the present embodiment, the mirror unit 1 has a short piece 1a. The short piece 1 a is formed integrally with the mirror unit 1. The width of the short piece 1a in the Z-axis direction is smaller than the width of the mirror unit 1 in the Z-axis direction.

  The short piece 1a is provided in the center part of the mirror part 1, and the mirror part 1 is connected with the fixing | fixed part 2 via the short piece 1a.

  The drive unit 3 and the drive unit 7 are arranged so as to be arranged in the Z-axis direction at a predetermined interval with respect to the end surface of the mirror unit 1.

  The drive unit 7 includes electrodes 7 a to 7 e and a plurality of insulating layers 71, and the structure thereof is the same as that of the drive unit 3. The drive circuit 8 applies voltages to the electrodes 7a to 7e of the drive unit 7, respectively. The configuration of the drive circuit 8 will be described later.

  In the present embodiment, the drive circuit 4 and the drive circuit 8 apply voltages to predetermined electrodes of the drive unit 3 and the drive unit 7, respectively.

  When the drive circuit 4 and the drive circuit 8 apply voltages to the electrodes having different heights of the drive unit 3 and the drive unit 7, the drive unit 3 and the drive unit 7 are statically connected between the electrodes of different heights and the mirror unit 1. Electric power is generated. Thereby, the mirror part 1 inclines two-dimensionally around the Z axis and the Y axis. Therefore, the reflection device according to the present embodiment can two-dimensionally reflect and scan light from a light source (not shown).

  A reflection device in which the mirror unit 1 is tilted about two axes (in this example, around the Z axis and the Y axis) is called a two-dimensional mirror.

  Note that the reflection device of the present embodiment may be used as a one-dimensional mirror by applying a voltage to the electrodes having the same height in the drive unit 3 and the drive unit 7.

  FIG. 7 is a schematic diagram showing the configuration of the drive circuit 4 and the drive circuit 8 of FIG.

  Since the configuration of the drive circuit 4 is the same as the configuration of the drive circuit 4 in FIG. 2 of the first embodiment, description thereof is omitted.

  The drive circuit 8 includes a DC power supply 81 and switching elements 8a to 8e. The switching elements 8a to 8e are connected between the DC power source 81 and the electrodes 7a to 7e of the drive unit 7, respectively. In the initial state, the switching elements 8a to 8e are off.

  Here, the set tilt angle of the mirror unit 1 in the reflection device of the present embodiment will be described.

  FIG. 8 is an explanatory diagram showing an example of the relationship between the tilt angle in the two-dimensional mirror and the application electrodes of the drive unit 3 and the drive unit 7.

  The tilt angle around the Y axis of the mirror unit 1 is θy, and the tilt angle around the Z axis is θz. The tilt angles θy1, θy3, θy5 and θz1 to θz5 in FIG. 8 have angle values set in advance.

  As shown in FIG. 8, when the mirror unit 1 is tilted so that the tilt angle around the Y axis is θy5 and the tilt angle around the Z axis is θz4, for example, the electrode 3e and the drive unit of the drive unit 3 A voltage is applied to the seventh electrode 7c. In this case, in FIG. 7, the switching element 4e of the drive circuit 4 and the switching element 8c of the drive circuit 8 are turned on. Accordingly, the mirror unit 1 is tilted so that the tilt angle around the Y axis is θy5 and the tilt angle around the Z axis is θz4. In FIG. 7, the tilt angle θz4 around the Z axis of the mirror unit 1 is not shown in order to facilitate the drawing.

  Here, the tilt angle θy of the mirror unit 1 can be calculated by a trigonometric function as shown in the following equation (2).

θy = tan ⁻¹ (nt / L2) (2)
In the above formula (2), t is a length obtained by adding the thickness of one electrode of the driving unit 3 to 50 μm and the thickness of one insulating layer 31 to 20 μm, and n is the initial position of the mirror unit 1 The number of electrodes (not including the electrode 3c) from the electrode 3c corresponding to is applied to the application electrode of the driving unit 3 is shown. For example, when a voltage is applied to the electrode 3e, n corresponds to 2. L2 is the distance between the center of the drive unit 3 and the center of the drive unit 7 in FIG.

(Fourth embodiment)
FIG. 9 is a schematic diagram illustrating a configuration of a reflecting device according to the fourth embodiment.

  As shown in FIG. 9, the reflection device according to the present embodiment is different from the reflection device according to the first embodiment in that a mirror portion 1 b is provided instead of the mirror portion 1.

  In the present embodiment, the mirror portion 1b has a hollow box-shaped cylindrical structure, and is on the side orthogonal to each of the light reflecting surface of the mirror portion 1b and the side surface facing the drive portion 3. Both side surfaces are opened. The light reflecting surface of the mirror portion 1b is made of a metal such as aluminum or gold. The mirror portion 1b having a hollow box-shaped cylindrical structure is manufactured by using a micro electro mechanical system (MEMS) that is generally known for application of semiconductor manufacturing technology.

  Advantages of the mirror portion 1b having a hollow box-shaped cylindrical structure will be described with reference to the following drawings.

  FIG. 10 is a schematic diagram showing a state in which the mirror portion 1b of FIG. 9 is tilted. In FIG. 10, for reference, the state in which the mirror unit 1 is inclined assuming that the area of the end surface of the mirror unit 1 in the first embodiment is equal to the area of the end surface of the mirror unit 1 b is also shown. Illustrated with a dotted line.

  Here, in order to improve the use efficiency of the driving force that tilts the mirror portion 1 b, that is, the electrostatic force, the end surface (hereinafter referred to as the “facing end surface”) 1 c facing the drive portion 3 of the mirror portion 1 b is It is preferable to be parallel to the end face. Hereinafter, it will be described in detail with reference to the drawings.

  As shown in FIG. 10, when the mirror unit 1b and the mirror unit 1 are in the initial position, that is, when the tilt angle is 0 °, they face the opposite end face 1c of the mirror unit 1b and the drive unit 3 of the mirror unit 1. A side end surface (hereinafter referred to as an opposing end surface) 1 d is parallel to the end surface of the drive unit 3.

  On the other hand, when the mirror unit 1b and the mirror unit 1 are tilted around the Z axis by electrostatic force, the facing end surface 1c of the mirror unit 1b having a hollow structure is parallel to the end surface of the drive unit 3, The opposed end surface 1 d of the mirror unit 1 that does not have a hollow structure is not parallel to the end surface of the drive unit 3.

  As described above, since the mirror portion 1b has a hollow box-shaped cylindrical structure, the opposite end surface 1c of the mirror portion 1b is parallel to the end surface of the drive portion 3 when the mirror portion 1b is inclined by electrostatic force.

  Thereby, the area which receives the electrostatic force by the drive part 3 in the opposing end surface 1c of the mirror part 1b becomes large, and the utilization efficiency of an electrostatic force improves. Thereby, the power saving of a reflection apparatus is realizable.

  Here, since the mirror part 1b shown in FIG. 9 has a hollow structure, the thickness of the mirror part 1b is larger than the thickness of the mirror part 1 of FIG. For this reason, the tilting operation of the mirror portion 1b may not be performed smoothly.

  In the present embodiment, the shape of the facing end surface 1c is formed as follows so that the tilting operation of the mirror portion 1b is facilitated.

  FIG. 11 is an enlarged view showing the shape of the opposed end surface 1c of the mirror portion 1b of FIG.

  As shown in FIG. 11A, the thickness of the region of the mirror portion 1b along the angle of the opposed end surface 1c of the mirror portion 1b is reduced.

  Further, as shown in FIG. 11B, one or a plurality of notches 1e are provided in the connecting portion of the facing end surface 1c of the mirror portion 1b.

  Further, as shown in FIG. 11 (c), the opposing piece 1f having the opposing end face 1c is provided with a hole 1g. A U-shaped hinge 1h is provided on the plane of the mirror portion 1b. In this case, when the hinge 1h is engaged with the hole 1g of the opposing piece 1f, the opposing piece 1f is constrained to the mirror part 1b while having a degree of freedom.

  With the configuration shown in FIGS. 11A to 11C described above, the tilting operation of the mirror portion 1b is smooth, and the opposed end surface 1c is reliably parallel to the end surface of the drive unit 3. Thereby, the area which receives the electrostatic force by the drive part 3 in the opposing end surface 1c of the mirror part 1b becomes large, and the utilization efficiency of an electrostatic force is improved more.

  FIG. 12 is a schematic diagram illustrating the configuration of the drive circuit 4 that performs the initialization process of the mirror unit 1b.

  The initialization process of the mirror unit 1b is the following process. That is, as described above, when the mirror portion 1b has a hollow structure, the mirror portion 1b may be in a free state when the drive circuit 4 is not driven and abnormal, and the position of the mirror portion 1b is specified. May be difficult. Processing for returning the mirror unit 1b to the initial position is referred to as initialization processing.

  As shown in FIG. 12, the drive circuit 4 includes five DC power supplies 41a to 41e. The five DC power supplies 41a to 41e apply voltages to the electrodes 3a to 3e of the drive unit 3, respectively. Thereby, different voltages can be simultaneously applied to all the electrodes 3 a to 3 e of the drive unit 3.

  In the present embodiment, the highest voltage V3 is applied to the electrode 3c corresponding to the initial position of the mirror portion 1b. In this case, the voltage applied to the electrode 3a is V1, the voltage applied to the electrode 3b is V2, the voltage applied to the electrode 3c is V3, the voltage applied to the electrode 3d is V4, and the voltage applied to the electrode 3e is Assuming V5, a voltage satisfying the relationship of the following formula (3) and the following formula (4) is applied to each electrode.

V1 <V2 <V3 (3)
V5 <V4 <V3 (4)
With such a configuration, the electrostatic force at the electrode 3c of the drive unit 3 is the strongest. Thereby, the mirror portion 1b is attracted to the electrode 3c and returned to the initial position.

(Fifth embodiment)
FIG. 13 is a schematic diagram illustrating a configuration of a reflecting device according to the fifth embodiment.

  As shown in FIG. 13, the reflection device according to the present embodiment is different from the reflection device according to the fourth embodiment in the connection method of the mirror unit 1b. Details will be described below.

  In the present embodiment, two rotation shafts 6a and 6b along the Z axis are rotatably connected to the end surfaces on both sides of the mirror portion 1b having a hollow structure. The two rotation shafts 6a and 6b are rotatably provided on the two fixed support columns 6, respectively.

  With such a configuration, when a voltage is applied to a predetermined electrode of the drive unit 3 by the drive circuit 4, the mirror unit 1b can be tilted around the Z axis.

(Effects of the reflecting device according to each of the above embodiments)
In each of the above-described embodiments, by applying a voltage to at least one of the electrodes 3a to 3e of the drive unit 3 by the drive circuit 4, the tilt angle of the mirror units 1 and 1b can be controlled with high accuracy and tilt. The corner can be increased or decreased.

  Moreover, since the drive parts 3 and 7 which incline the mirror parts 1 and 1b do not exist on the mirror parts 1 and 1b, manufacture can be facilitated and the mirror parts 1 and 1b can be reduced in weight. Further, it is possible to reflect and scan light by using the entire mirror unit 1 or 1b as a reflection surface. Thereby, the utilization factor of light can be improved.

  Further, by using the memory 5 in which the relationship between the tilt angle of the mirror unit 1 and 1b and the applied electrode is stored in advance, the drive units 3 and 7 are not provided without detecting means for detecting the tilt angle of the mirror unit 1 and 1b. Thus, the mirror parts 1 and 1b can be inclined. Thereby, size reduction of a reflecting device can be achieved.

  In each of the above embodiments, the mirror units 1 and 1b correspond to the movable plate, the drive unit 3 corresponds to the first drive unit, the drive unit 7 corresponds to the second drive unit, and the electrodes 3a to 3e. Corresponds to the first electrode, the electrodes 7a to 7e correspond to the second electrode, the drive circuits 4 and 8 correspond to the control circuit, the hinge 11 corresponds to the connecting portion, and the opposing end surface 1c is the movable plate. It corresponds to the end face.

(Other embodiments)
In each of the above embodiments, the drive unit 3 and the drive unit 7 have five electrodes 3a to 3e and electrodes 7a to 7e, respectively. However, the present invention is not limited to this, and less than 5 or 6 You may have the above electrode.

  In driving, the voltages applied to the electrodes 3a to 3e and the electrodes 7a to 7e may be different for each electrode.

  Furthermore, in the second and fifth embodiments, a plurality of drive units may be provided.

(Reflecting device according to reference form)
Hereinafter, the reflecting device according to the reference embodiment will be described with reference to the drawings.

  Unlike the reflecting device according to each of the above embodiments, the reflecting device according to the reference embodiment generates an electrostatic force by the mirror driving unit and tilts the mirror unit 1 by the generated electrostatic force. The tilt angle of the mirror unit 1 is detected by a position sensor. The calculation unit reads the detection value detected by the position sensor and feeds it back to the mirror drive unit, whereby the mirror unit 1 is tilted to have a desired tilt angle. Hereinafter, each reference form will be described in detail.

(First reference form)
FIG. 14 is a schematic diagram showing the configuration of the reflection device according to the first reference embodiment.

  As shown in FIG. 14, the reflection device according to the present embodiment is different from the reflection device according to the first embodiment in that a mirror driving unit 10 including electrodes is provided, instead of the driving circuit 4. Are that the operation unit 9 is provided, the position sensor 11 is provided instead of the drive unit 3, and the memory 5 is not provided.

  In this reference embodiment, the mirror driving unit 10 is provided below the mirror unit 1.

  When a voltage is applied to the mirror driving unit 10 by the calculation unit 9, an electrostatic force is generated between the mirror driving unit 10 and the mirror unit 1. Thereby, the mirror part 1 inclines around the Z-axis. By tilting the mirror unit 1, light from a light source (not shown) can be reflected and scanned one-dimensionally.

  The position sensor 11 has a laminated structure of a plurality of electrodes 11a to 11e having a thickness of 50 μm, for example. An insulating layer 12 made of, for example, silicon oxide having a thickness of, for example, 20 μm is provided between the electrodes.

  Here, the position sensor 11 is provided at a predetermined interval (for example, 5 μm) with respect to the end face of the mirror unit 1. In the present embodiment, the height of the mirror unit 1 is set to be substantially the same as the height of the electrode 11a of the position sensor 11. The position of the mirror unit 1 is set as an initial position.

  The calculation unit 9 applies a voltage that does not reach the driving force for tilting the mirror unit 1 to each electrode of the position sensor 11 at the same time, thereby obtaining a capacitance between each electrode and the mirror unit 1. Detect each.

  And the calculating part 9 calculates the tilt angle of the mirror part 1 based on the position of the electrode in which the largest electrostatic capacitance generate | occur | produced between the mirror parts 1 among the detected electrostatic capacitances, and the said initial position. .

  When there is an error between the calculated tilt angle and the desired tilt angle, the calculation unit 9 feedback-controls the mirror driving unit 10 so that the mirror unit 1 has a desired tilt angle.

(Second reference form)
FIG. 15 is a schematic diagram illustrating a configuration of a reflection device according to the second reference embodiment.

  As shown in FIG. 15, the reflection device according to this embodiment is different from the reflection device according to the first embodiment in that the connection method of the mirror unit 1 is different and an electrode is used instead of the mirror driving unit 10. Two mirror driving units 10a and 10b are provided. The mirror driving units 10a and 10b perform the same operation as the mirror driving unit 10 of the first reference embodiment. Details will be described below.

  In the present embodiment, two rotation shafts 6a along the Z axis are connected to end surfaces on both sides of the mirror portion 1 so as to be rotatable. The two rotation shafts 6a are rotatably provided on the two fixed support columns 6, respectively.

  The mirror driving unit 10a and the mirror driving unit 10b are provided below the mirror unit 1 so as to be arranged in the Y-axis direction. The mirror driving unit 10a is provided on the position sensor 11 side.

  With such a configuration, a voltage is applied to the mirror driving unit 10a or the mirror driving unit 10b by the calculation unit 9, whereby the mirror unit 1 can be tilted around the Z axis.

  When a voltage is applied to the mirror driving unit 10a by the calculation unit 9, the mirror unit 1 is inclined so that one end side approaches the mirror driving unit 10a, and the voltage is applied to the mirror driving unit 10b by the calculation unit 9. When this is done, the mirror unit 1 is tilted so that the other end approaches the mirror driving unit 10b.

  The calculation unit 9 applies a voltage that does not reach the driving force for tilting the mirror unit 1 to each electrode of the position sensor 11 at the same time, thereby obtaining a capacitance between each electrode and the mirror unit 1. Detect each.

  And the calculating part 9 calculates the tilt angle of the mirror part 1 based on the position of the electrode in which the largest electrostatic capacitance generate | occur | produced between the mirror parts 1 among the detected electrostatic capacitances, and the said initial position. .

  When there is an error between the calculated tilt angle and the desired tilt angle, the calculation unit 9 performs feedback control on the mirror driving units 10a and 10b so that the mirror unit 1 has a desired tilt angle.

(Third reference form)
FIG. 16 is a schematic diagram illustrating a configuration of a reflecting device according to the third reference embodiment.

  As shown in FIG. 16, the reflection device according to the present reference embodiment is different from the reflection device according to the first reference embodiment in that the shape of the mirror unit 1 is different and the position sensor has the same configuration as the position sensor 11. 13 is provided, and mirror drive units 10 a and 10 b are provided instead of the mirror drive unit 10.

  Since the mirror part 1 is the same as the shape of the mirror part 1 of the reflecting device according to the third embodiment, the description thereof is omitted.

  The position sensor 11 and the position sensor 13 are respectively arranged at a position opposite to the fixed portion 2 with a predetermined distance from the end face of the mirror portion 1.

  The mirror driving unit 10a and the mirror driving unit 10b are provided below the mirror unit 1 so as to be aligned in the Z-axis direction.

  With such a configuration, when the voltage is applied to the mirror driving unit 10a or the mirror driving unit 10b by the arithmetic unit 9, the mirror unit 1 can be tilted around the Y axis.

  Further, the mirror unit 1 can be tilted around the Z-axis by applying voltages to the mirror driving unit 10a and the mirror driving unit 10b respectively by the arithmetic unit 9.

  The calculation unit 9 applies a voltage that does not reach a driving force for tilting the mirror unit 1 to each electrode of the position sensors 11 and 13 simultaneously, thereby electrostatically connecting each electrode and the mirror unit 1. Each capacity is detected.

  And the calculating part 9 calculates the tilt angle of the mirror part 1 based on the position of the electrode in which the largest electrostatic capacitance generate | occur | produced between the mirror parts 1 among the detected electrostatic capacitances, and the said initial position. .

  When there is an error between the calculated tilt angle and the desired tilt angle, the calculation unit 9 performs feedback control on the mirror driving units 10a and 10b so that the mirror unit 1 has a desired tilt angle.

(4th reference form)
FIG. 17 is a schematic diagram illustrating a configuration of a reflection device according to the fourth reference embodiment.

  As shown in FIG. 17, the reflection device according to this embodiment is different from the reflection device according to the first embodiment in that a mirror portion 1 b is provided instead of the mirror portion 1.

  Since the mirror part 1b is the same as the shape of the mirror part 1b of the reflecting device according to the fourth embodiment, the description thereof is omitted.

  In the present embodiment, since the mirror portion 1b has a hollow box structure, the opposite end surface 1c of the mirror portion 1b is parallel to the end surface of the position sensor 11 when the mirror portion 1b is inclined by an electrostatic force. Thereby, the detection of the electrostatic capacitance by the position sensor 11 is performed more accurately.

  The calculation unit 9 applies a voltage that does not reach the driving force for tilting the mirror unit 1b to each electrode of the position sensor 11 at the same time, thereby obtaining a capacitance between each electrode and the mirror unit 1b. Detect each.

  And the calculating part 9 calculates the tilt angle of the mirror part 1b based on the position of the electrode where the largest electrostatic capacitance generate | occur | produced between the mirror parts 1b among the detected electrostatic capacitances, and the said initial position. .

  When there is an error between the calculated tilt angle and the desired tilt angle, the calculation unit 9 feedback-controls the mirror drive unit 10 so that the mirror unit 1b has the desired tilt angle.

(Effects of the reflecting device according to each of the above reference forms)
In each of the above reference embodiments, the drive units 10, 10a, 10b for tilting the mirror units 1, 1b and the position sensors 11, 13 for detecting the tilt angle of the mirror units 1, 1b do not exist on the mirror units 1, 1b. Thus, it is possible to facilitate manufacturing and reduce the weight of the mirror portions 1 and 1b. Further, it is possible to reflect and scan light by using the entire mirror unit 1 or 1b as a reflection surface. As a result, the utilization factor of light can be improved, and the tilt angle can be set with high accuracy by the feedback control.

(Other reference forms)
In the first, second, and fourth reference embodiments, one position sensor is provided. However, the present invention is not limited to this, and two position sensors are used to detect more accurate capacitance. The above position sensor may be provided.

  The present invention can be used as a projector for reflecting and non-reflecting light, and as an optical scanning device for scanning light.

It is a schematic diagram which shows the structure of the reflecting device which concerns on 1st Embodiment. It is a schematic diagram which shows the structure of the drive circuit of FIG. FIG. 2 is an explanatory diagram illustrating an example of a relationship between a specific example of a tilt angle stored in a memory of FIG. 1 and an application electrode of a driving unit. It is a schematic diagram which shows an example of the fixing method of a mirror part and a fixing | fixed part. It is a schematic diagram which shows the structure of the reflecting device which concerns on 2nd Embodiment. It is a schematic diagram which shows the structure of the reflection apparatus which concerns on 3rd Embodiment. It is a schematic diagram which shows the structure of the drive circuit of FIG. 6, and a drive circuit. It is explanatory drawing which shows an example of the relationship between the tilt angle in a two-dimensional mirror, a drive part, and the application electrode of a drive part. It is a schematic diagram which shows the structure of the reflecting device which concerns on 4th Embodiment. It is a schematic diagram which shows the state which inclined the mirror part of FIG. It is an enlarged view which shows the shape of the opposing end surface of the mirror part of FIG. It is a schematic diagram which shows the structure of the drive circuit which performs the initialization process of a mirror part. It is a schematic diagram which shows the structure of the reflecting device which concerns on 5th Embodiment. It is a schematic diagram which shows the structure of the reflection apparatus which concerns on a 1st reference form. It is a schematic diagram which shows the structure of the reflection apparatus which concerns on a 2nd reference form. It is a schematic diagram which shows the structure of the reflection apparatus which concerns on a 3rd reference form. It is a schematic diagram which shows the structure of the reflection apparatus which concerns on a 4th reference form.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1b Mirror part 1a Short piece 1c, 1d Opposing end surface 1e Notch 1f Opposing piece 1g Hole part 1h, 11 Hinge 2 Fixing part 3, 7 Driving part 3a-3e, 7a-7e Electrode 4, 8 Driving circuit 4a-4e, 8a to 8e Switching element 5 Memory 6 Fixed column 6a, 6b Rotating shaft 9 Arithmetic unit 10, 10a, 10b Mirror drive unit 11, 13 Position sensor 11a-11e, 13a-13e Electrode 12, 14 Insulating layer 31, 71 Insulating layer 41, 41a to 41e, 81 DC power supply

Claims (10)

A movable plate having a reflecting surface for reflecting light;
A fixed portion for tiltably supporting the movable plate;
At least one drive unit arranged to face the end face of the movable plate;
A control circuit for controlling the drive unit,
The driving unit includes a plurality of stacked electrodes,
An insulating layer is interposed between the plurality of electrodes,
The control circuit selectively applies a voltage to at least one electrode of the plurality of electrodes of the driving unit, whereby an electrostatic force is applied between the electrode to which the voltage is applied and the end surface of the movable plate. A reflection device characterized by generating A movable plate having a reflecting surface for reflecting light;
A fixed portion for tiltably supporting the movable plate;
First and second drive units arranged to face the end face of the movable plate;
A control circuit for controlling the drive unit,
Each of the first driving units includes a plurality of stacked first electrodes,
Each of the second driving units includes a plurality of stacked second electrodes,
An insulating layer is interposed between the plurality of first and second electrodes,
The control circuit selectively applies a voltage to at least one of the plurality of first electrodes of the first driving unit, and controls the plurality of second electrodes of the second driving unit. Among them, by selectively applying a voltage to at least one electrode, an electrostatic force is generated between the first and second electrodes to which the voltage is applied and the end face of the movable plate. Reflector. The reflection device according to claim 1, wherein the control circuit applies a voltage to two of the plurality of electrodes of the driving unit. 4. The reflection device according to claim 1, wherein the control circuit applies a voltage to at least two of the plurality of electrodes of the driving unit in an initial state. The control circuit applies a voltage to at least one of the plurality of first electrodes of the first driving unit and at least one of the plurality of second electrodes of the second driving unit. The reflection device according to claim 2, wherein The control circuit applies voltage to two electrodes of the plurality of second electrodes of the second driving unit and at least one electrode of the plurality of first electrodes of the first driving unit. The reflection device according to claim 2, wherein The control circuit applies a voltage to at least two of the plurality of first electrodes of the first driving unit in an initial state, and at least two of the plurality of second electrodes of the second driving unit. 7. The reflection device according to claim 2, wherein a voltage is applied to the two electrodes. The reflection apparatus according to claim 1, wherein the movable plate is connected to the fixed portion by one or a plurality of connecting portions. The movable plate is a rectangular parallelepiped having a hollow structure,
The rectangular parallelepiped has an end surface facing the side surface of the drive unit,
9. The rectangular parallelepiped is formed so that the rectangular parallelepiped is deformable so that the end face is maintained parallel to the side surface of the drive unit as the rectangular parallelepiped is inclined. Reflector. The said fixing | fixed part contains the rotation axis | shaft which supports the said movable plate so that rotation is possible, and the fixed support | pillar which supports the said rotation axis so that rotation is possible. The reflecting device as described.

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