JP2004198648A - Planar type actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar type actuator capable of keeping the ratio of resonance frequency between an outer movable plate and an inner movable plate large and realizing raster scanning when it is used for scanning by deflecting light. <P>SOLUTION: The planar type actuator is equipped with: an outer movable part 17 equipped with an outer movable plate 3 by pivotally supporting it on an outer fixed part 1 with an outer torsion bar 2; an inner movable part 16 equipped with the inner movable plate 5 by pivotally supporting it on an inner fixed part 20 with an inner torsion bar 4; and a driving means for driving the plates 3 and 5. The movable parts 17 and 16 are formed of materials having different rigidity, and the movable part 16 is fixed on the plate 3 of the movable part 17 so that the axial direction of the torsion bar 2 is orthogonal to the axial direction of the torsion bar 4. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a planar actuator, and more particularly, to a two-dimensional scanning type planar actuator manufactured by a micromachining technology to which a semiconductor manufacturing technology is applied.
[0002]
[Prior art]
This type of planar actuator is used for deflection scanning of a light beam such as a laser beam or the like, and includes an electromagnetic type using an electromagnetic force and an electrostatic type using an electrostatic force.
[0003]
Hereinafter, an example of an electromagnetic actuator will be described.
FIG. 10 shows an example of a planar type electromagnetic actuator.
In this two-dimensional scanning type planar electromagnetic actuator, a frame-shaped outer movable plate 3 is rotatably supported by an outer torsion bar 2 on an outer fixed portion 1 of a silicon substrate, and an outer torsion bar 2 is attached to the outer movable plate 3. The flat inner movable plate 5 is rotatably supported by an inner torsion bar 4 whose axial direction is orthogonal to the inner movable plate 5. The outer fixed portion 1, the outer and inner torsion bars 2, 4 and the outer and inner movable plates 3, 5 are integrally formed of a semiconductor substrate. A second drive coil 6 (schematically indicated by a single line in the figure) that generates a magnetic field when energized is formed on the outer movable plate 3, and the second drive coil 6 includes a pair of outer coils formed on the outer fixed portion 1. It is electrically connected to the electrode terminals 7A, 7A via one of the outer torsion bars 2. A reflective mirror 8 is formed at the center of the inner movable plate 5, and a first drive coil 9 (schematically shown by one line in the figure) that generates a magnetic field when energized is formed at a peripheral edge thereof. The first drive coil 9 is electrically connected to the pair of inner electrode terminals 10A and 10B of the outer fixed portion 1 through the other side of the outer torsion bar 2 from one side of the inner torsion bar 4 and the outer movable plate 3. I do. Further, a pair of static magnetic field generating means (for example, permanent magnets) is applied to the drive coil portions on the opposite sides of the movable plates 3 and 5 parallel to the axial directions of the outer and inner torsion bars 2 and 4, respectively. Around the movable plate. In the example of FIG. 10, a static magnetic field is applied to the upper insulating substrate 15 and the lower insulating substrate 16 made of, for example, glass, which join the pair of permanent magnets 11 </ b> A, 11 </ b> B to 14 </ b> A, 14 </ b> B above and below the outer fixed part 1. The first and second driving coils 6 and 9 are arranged so as to be vertically displaced so as to cross in a direction parallel to the outer and inner movable plates 3 and 5 (for example, see Patent Document 1).
[0004]
The electromagnetic actuator having such a configuration has an outer side and an outer side due to an interaction between a magnetic field generated by applying a current to the first and second drive coils 6 and 9 and a static magnetic field generated by the permanent magnets 11A, 11B to 14A and 14B. The inner movable plates 3 and 5 are driven.
[0005]
That is, on both sides of the outer and inner movable plates 3, 5, the first and second drive coils 6, 9 are traversed along the plane of the outer and inner movable plates 3, 5 by the permanent magnets 11A, 11B to 14A, 14B. A static magnetic field is formed in various directions. When an electric current is applied to the first and second drive coils 6 and 9 in the static magnetic field, an electromagnetic force acts on both ends of the outer and inner movable plates 3 and 5 in a direction according to Fleming's left hand rule, thereby causing the outer and inner movable plates 3 and 5 to move outward. And the inner movable plates 3 and 5 rotate. When the outer and inner movable plates 3, 5 rotate, the torsion bars 2, 4 are twisted to generate a spring reaction force, and the outer and inner movable plates 3, 5 rotate to a position where the electromagnetic force and the spring reaction force balance. I do. The rotation angles of the outer and inner movable plates 3, 5 are proportional to the current flowing through the first and second drive coils 6, 9, and the currents are controlled to control the rotation angles of the outer and inner movable plates 3, 5. it can. By setting the frequency of the alternating current flowing through the first and second drive coils 6 and 9 to be the same as the resonance frequency defined by the material and shape of the outer and inner torsion bars 2 and 4, the current value Is obtained. Accordingly, the direction of reflection of light such as laser light incident on the reflection mirror 8 can be freely controlled, and the outer and inner movable plates 3 and 5 are continuously and repeatedly operated to scan light such as scanning of laser light. Becomes possible.
[0006]
[Patent Document 1]
Japanese Patent No. 2722314
[0007]
[Problems to be solved by the invention]
By the way, in order to perform two-dimensional scanning with light such as a laser beam to detect an object such as a laser radar or to display an image such as a picture or a character, raster scanning is generally performed. In this case, horizontal scanning and vertical scanning are performed. The larger the scanning frequency ratio, the better. However, in the above-described conventional planar actuator, the outer and inner torsion bars 2 and 4 are formed of the same material (the same silicon as the semiconductor substrate material), so that even if the cross-sectional shape and the like are different, the rigidity thereof is not increased. It is difficult to greatly change For this reason, the resonance frequency ratio between the outer movable plate 3 and the inner movable plate 5 cannot be made large, and when performing raster scanning, the scanning trajectory becomes a Lissajous curve. Therefore, when attempting to detect an object or display an image with a conventional planar actuator, it is necessary to control the Lissajous curve.However, the Lissajous curve has a problem that the curve shape changes greatly due to a slight difference in frequency, and thus it is difficult to control the Lissajous curve. .
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a planar actuator that can increase the resonance frequency ratio between the outer movable plate and the inner movable plate and enables raster scanning when used for light deflection scanning or the like. The purpose is to provide.
[0009]
[Means for Solving the Problems]
For this purpose, the first aspect of the present invention provides an outer movable portion having an outer movable plate rotatably supported by an outer torsion bar on an outer fixed portion, and an inner movable plate having an inner torsion bar on the inner fixed portion. An inner movable portion rotatably supported and provided with driving means for driving each of the movable plates, wherein the outer movable portion and the inner movable portion are formed of materials having different rigidities, and the outer torsion is formed. The inner movable portion is fixed to the outer movable plate of the outer movable portion so that the axial direction of the bar is orthogonal to the axial direction of the inner torsion bar.
[0010]
With such a configuration, the outer movable portion and the inner movable portion are formed of materials having different rigidities, the outer movable plate of the outer movable portion is supported on the outer fixed portion by the outer torsion bar, and the outer movable plate is driven by the driving means. Rotating with the inner movable portion, the inner movable plate of the inner movable portion is supported on the inner fixed portion by an inner torsion bar orthogonal to the axial direction of the outer torsion bar, and the inner movable plate is rotated by the driving means. This makes it possible to increase the drive frequency ratio between the outer movable plate and the inner movable plate.
[0011]
Specifically, the planar type actuator of the present invention is configured such that one of the outer movable portion and the inner movable portion is formed using silicon as a main material for determining rigidity, and the other is, It is preferable to use a material having a lower rigidity than the silicon as a main material for determining the rigidity. In this case, as in claim 3, the inner movable portion may be formed of silicon, and the outer movable portion may be formed of a material having a lower rigidity than silicon. In this case, as described in claim 4, The outer movable part may be formed of plastic.
[0012]
Further, the inner movable portion is stuck on the upper surface of the outer movable plate. Alternatively, the inner movable portion may be configured to be fitted into the outer movable plate as in claim 6. In this case, a relief may be provided at a portion of the outer movable plate corresponding to the inner movable plate so that the inner movable plate does not come into contact with the outer movable plate when rotating.
[0013]
In claim 8, the driving means includes a driving coil laid on each of the movable plates, and a static magnetic field generating means for applying a static magnetic field to each of the driving coils, and a current flows through each of the driving coils. Each of the movable plates is driven by the electromagnetic force generated by the above. In this case, it is preferable that the drive coil laid on the inner movable plate is drawn out from the vicinity of the rotation axis of the outer movable plate to the outside via the outer torsion bar. At this time, a relay terminal of the drive coil laid on the inner movable plate as in claim 10 is provided on the inner fixed portion and the outer movable plate near a rotation axis of the outer movable plate, and the relay terminals are provided. The terminals may be respectively wire-bonded.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the same elements as those of the prior art in FIG. 10 are described using the same reference numerals.
FIG. 1 is a schematic configuration diagram showing an embodiment of a planar actuator according to the present invention, which is applied to an optical scanner. FIG. 2 is an exploded perspective view of FIG.
In FIG. 1, the planar actuator according to the present embodiment enables raster scanning of light, and includes an inner movable portion 16, an outer movable portion 17, a first driving coil 9 as a driving unit, and a second driving device. It comprises a coil 6 and static magnetic field generating means 18A, 18B, 19A, 19B.
[0015]
Then, the inner movable portion 16 is bonded and fixed to the central portion of the outer movable plate 17 so that the respective rotation axes are orthogonal to each other, and the first drive coil laid on the inner movable plate 5 of the inner movable portion 16 which will be described later. 9 and the second drive coil 6 laid on the later-described outer movable plate 3 of the outer movable portion 17, and the static magnetic field generating means 18 </ b> A to 18 </ b> A disposed outside the outer movable portion 17. The inner movable plate 5 and the outer movable plate 3 are rotated by an electromagnetic force generated by interaction with the static magnetic field of 19B.
Hereinafter, the configuration of the present embodiment will be described in detail with reference to FIGS.
[0016]
The inner movable portion 16 is for scanning a light beam. The inner movable plate 5 is rotatably supported by an inner torsion bar 4 on an inner fixed portion 20 provided outside the inner movable plate 5. For example, a silicon substrate having a large rigidity (for example, a Young's modulus of about 190 GPa) is applied to the inner fixed portion 20, the inner torsion bar 4, and the inner movable plate by applying a micromachining technology applied to a semiconductor manufacturing technology. The portion other than 5 is formed by anisotropic etching so as to penetrate vertically.
[0017]
A first drive coil 9 is laid on the surface of the inner movable plate 5 along the periphery of the inner movable plate 5. The first drive coil 9 is provided on the first movable coil 5 near the opposite side of the inner movable plate 5 parallel to the inner torsion bar 4 due to the interaction between a current flowing through the coil and a static magnetic field generated from static magnetic field generating means 18A, 18B described later. An electromagnetic force is generated in the drive coil 9 to rotate the inner movable plate 5, and a first relay terminal 22 </ b> A provided on the inner fixed portion 20 via the inner torsion bar 4 by the first lead wire 21. , 22A. The first relay terminals 22A, 22A are provided near the center line X of the inner movable plate 5 orthogonal to the axis of the inner torsion bar 4, as shown in FIG. The center line X substantially coincides with an axis of the outer torsion bar 2 of the outer movable portion 17 described later. In addition, a reflection mirror 8 that reflects the light beam is provided on the central surface of the inner movable plate 5. The reflection mirror 8 is, for example, a thin film formed of aluminum by vacuum evaporation or the like.
[0018]
The outer movable portion 17 is configured such that the outer movable plate 3 is rotatably supported by an outer torsion bar 2 on an outer fixed portion 1 provided outside the outer movable plate 3. The movable portion 16 is integrally formed by die molding or punching a plastic plate material with a plastic material having a lower rigidity than the silicon substrate. As the plastic material, for example, a polyimide material can be used. The rigidity of the plastic can be adjusted by adding a filler material such as glass fiber, carbon fiber, and metal fiber.
[0019]
The axial direction of the inner torsion bar 4 is orthogonal to the axial direction of the outer torsion bar 2 within the frame P indicated by a broken line in FIG. As described above, the inner movable portion 16 is adhered and held, and the outer movable plate 3 is rotated integrally with the inner movable portion 16 in a direction orthogonal to the rotation direction of the inner movable plate 5, whereby the inner movable plate 16 is rotated. The light reflected by the reflection mirror 8 of the inner movable plate 5 in combination with the rotation of the inner movable plate 5 can be scanned two-dimensionally. The inner movable part 16 is not bonded to the outer movable plate 3 of the outer movable part 17, but is loaded into the mold and then injected with a plastic resin to form the outer movable part 17. As shown in FIG. 3, both movable portions may be integrally formed by insert molding. Alternatively, both movable parts may be integrated by outsert molding in which the outer movable part 17 is formed of silicon, and the inner movable part 16 formed of plastic resin is fitted and fixed to the outer movable plate 3 of the outer movable part 17. Good.
[0020]
A relief portion 23 is provided at a central portion of the outer movable plate 3 corresponding to the inner movable plate 5 so that the inner movable plate 5 does not come into contact with the outer movable plate 3 when rotating. . The escape portion 23 may be a hole or a through hole as shown in FIG. 2, and grooves provided on both sides of the rotation axis Y of the inner movable plate 5 as shown in FIG. 24A, 24A. In addition, when the rotation angle of the inner movable plate 5 is small and there is no possibility of contact with the outer movable plate 3, the escape portion 23 may not be provided. When the outer movable plate 3 is provided with a through hole as the escape portion 23, the reflection mirror 8 may be provided on the back surface of the inner movable plate 5.
[0021]
Then, as shown in FIG. 2, a second drive coil 6 is laid on the outer movable plate 3 along the peripheral edge. The second drive coil 6 is provided in the vicinity of the opposite side of the outer movable plate 3 parallel to the outer torsion bar 2 due to the interaction between a current flowing through the coil and a static magnetic field generated from static magnetic field generating means 19A and 19B described later. An electromagnetic force is generated in the drive coil 6 to rotate the outer movable plate 3, and an outer electrode provided on the outer fixed portion 1 via one outer torsion bar 2 by a second lead wire 25. Connected to terminals 7A, 7A. In the outer movable plate 3, second relay terminals 26A, 26A are provided in the vicinity of the rotation axis of the outer torsion bar 2 so as to face the first relay terminals 22A, 22A of the first drive coil 9. It is connected to the inner electrode terminals 10A, 10A provided on the outer fixed part 1 via the other outer torsion bar 2 by a third lead wire 27. Then, as shown in FIG. 1, the first relay terminals 22A, 22A and the second relay terminals 26A, 26A are connected by wire bonding with a bonding wire W of, for example, gold. The first and second relay terminals 22A, 22A, 26A, 26A can reduce the moment received by the bonding wire W when the outer movable plate 3 rotates, and can suppress the disconnection of the bonding wire W. It is preferable that the outer torsion bar 2 is provided in the vicinity of the rotation axis, but it is not necessarily limited to the vicinity of the rotation axis.
[0022]
Outside the outer fixed part 1 of the outer movable part 17, static magnetic field generating means 18A, 18B, 19A, 19B are provided with opposite magnetic poles facing each other with the outer movable plate 3 and the inner movable plate 5 interposed therebetween. Are located. The static magnetic field generating means 18A, 18B, 19A, 19B are, for example, a pair of permanent magnets, and the static magnetic field generating means 18A, 18B are located near the opposite side of the inner movable plate 5 parallel to the axial direction of the inner torsion bar 4. And the static magnetic field generating means 19A and 19B provide the current flowing through the second drive coil 6 near the opposite side of the outer movable plate 3 parallel to the axial direction of the outer torsion bar 2. And a magnetic field parallel to the surfaces of the outer and inner movable plates 3 and 5 which are orthogonal to each other.
[0023]
According to the planar actuator having such a configuration, it is possible to drive the highly rigid inner movable portion 16 made of silicon at a high resonance frequency and drive the less rigid outer movable portion 17 made of plastic at a low resonance frequency. Thus, the resonance frequency ratio between the inner movable portion 16 and the outer movable portion 17 can be increased. Therefore, the raster scanning of the laser light can be easily performed by controlling the driving of the inner movable portion 16 and the outer movable portion 17, and the planar type suitable for the optical scanning device for object detection and image display using the laser light or the like. An actuator can be provided. In addition, since the rigidity of polyimide is low and the movable plate can be stopped at a predetermined position with a small force, the outer movable plate 3 can be rotated in a stepwise manner, and the horizontal scanning of the laser beam can be performed. It becomes possible. In addition, polyimide has good impact resistance, and can improve durability against destruction of the outer torsion bar 2 and the like. Further, since the inner movable portion 16 is formed of highly rigid silicon, deformation such as warpage of the inner movable plate 5 can be suppressed, and when applied to an optical scanner, light scanning accuracy can be improved. . Further, when the inner movable portion is formed of silicon and the outer movable portion is formed of plastic, the number of the inner movable portion formed from one silicon substrate increases because the shape of the inner movable portion is small, and the manufacturing cost is reduced. Can be reduced. Also, the outer movable portion having a large shape can be easily manufactured by molding or punching a plastic material, thereby reducing the manufacturing cost. Therefore, an inexpensive planar actuator can be provided. The inner movable portion 16 may be made of plastic, and the outer movable portion 17 may be made of silicon.
[0024]
Next, a method of manufacturing a planar actuator according to the present invention will be described.
First, a method of manufacturing the inner movable portion 16 made of silicon will be described with reference to FIGS. FIG. 5 shows a step of forming the first drive coil 9 in a series of manufacturing steps, and FIG. 6 shows a step of etching the silicon substrate. Each of the figures is a cross-sectional view taken along line AOB of FIG.
[0025]
First, as shown in FIG. 5, in step (a), a silicon substrate 27 of an SOI (Silicon On Insulator) wafer is prepared. For example, the silicon substrate 27 has a silicon active layer 27a having a thickness of 100 μm and a silicon active layer 27a having a thickness of 1 μm. _Two And a silicon support substrate 27c having a thickness of 400 μm.
[0026]
Next, in the step (b), the upper and lower surfaces of the silicon substrate 27 are thermally oxidized to form a SiO.sub. _Two The insulating layers 27d and 27e are formed. Then, the first-layer drive coil 9a of the first drive coil 9 is formed on the insulating layer 27d on the silicon active layer 27a side. In the method of forming the first-layer drive coil 9a, first, for example, a thin film of aluminum as a highly conductive metal is formed with a thickness of about 2 μm on almost the entire surface of the silicon substrate 27 by a vacuum film forming technique such as sputtering. Next, a resist is applied thereon, and a portion corresponding to the inner movable plate 5 corresponds to a first contact portion 9b for making electrical connection with the first-layer driving coil 9a and the second-layer driving coil. A coil-shaped resist pattern is formed while leaving a portion of the resist. Then, using this as a mask, the aluminum thin film is etched, and then the resist is removed to form the first-layer drive coil 9a and the first contact portion 9b. Either wet etching using an etchant or dry etching using a reactive gas can be used for the etching.
[0027]
In step (c), a first insulating layer 28a of photosensitive polyimide is formed on the first-layer driving coil 9a to a thickness of about 2 μm. In this case, unillustrated first relay terminals 22A and 22A on the first contact portion 9b and the portion corresponding to the inner torsion bar 4 corresponding to the first lead wire 21 and the inner fixing portion 20 (see FIG. 2). The first insulating layer 28a is formed except for the part corresponding to ()). Further, in the same manner as in the step (b), a thin film of aluminum is formed to a thickness of about 2 μm on the entire surface of the silicon substrate 27, and this is etched to form the second-layer drive coil 9c, the second contact portion 9d, and the first lead wire 21. And, the first relay terminals 22A, 22A (see FIG. 2) not shown are formed.
[0028]
Next, in the step (d), the second insulating layer 28b made of a photosensitive polyimide is formed by covering the upper part of the second-layer drive coil 9c, the second contact part 9d and the first lead wire 21 in the same manner as the step (c). To form This serves as a protective film for the purpose of preventing corrosion of the second-layer drive coil 9c and the first lead wire 21.
[0029]
Next, as shown in FIG. 6, the silicon substrate 27 is etched.
First, in the step (a), a portion corresponding to the inner movable plate 5, the inner torsion bar 4, and the inner fixed portion 20 of the silicon substrate 27 is covered with a resist mask, _Two Is removed by etching. Furthermore, SiO _Two The exposed silicon active layer 27a is removed by anisotropic etching in the thickness direction. In this case, the etching is SiO _Two 5, a concave portion 29 is formed as shown in FIG. 5, and the inner movable plate 5, the inner torsion bar 4, and a portion corresponding to the inner fixed portion 20 are connected to each other by a silicon support substrate 27c. A part 16 is formed.
[0030]
Further, in the step (b), a portion corresponding to the inner fixing portion 20 on the lower surface side of the silicon substrate 27 is masked with a resist, _Two Is removed by etching the insulating layer 27e. Further, the exposed support substrate 27c of the silicon substrate 27 is _Two Is etched in the thickness direction up to the intermediate layer 27b. Then, the SiO exposed by this etching _Two When the intermediate layer 27b is removed by etching, the recess 29 of FIG. 6 penetrates the silicon substrate 27 in the vertical direction. Then, when a reflective film of aluminum or the like is vacuum-formed at the center of the upper surface of the inner movable plate 5 to form the reflective mirror 8, the inner movable portion 16 shown in FIG. 2 is formed.
[0031]
Next, a manufacturing process of the outer movable portion 17 will be described with reference to FIGS.
First, as shown in FIG. 7, a polyimide resin 30 is poured into a molding die 29, dried at 80 ° C., and baked at 400 ° C. for 8 hours to be cured. The mold is formed to be about 10 times thicker so that the thickness of the outer torsion bar 2 and the thickness of the outer movable plate 3 become predetermined after firing. Then, the temperature is returned to room temperature after firing, and the mold is released due to a difference in thermal expansion coefficient between the molding die and the polyimide substrate.
[0032]
Alternatively, as shown in FIG. 8, a plastic plate material 31 may be stamped out to cut out a polyimide substrate 32 to be the outer movable portion 17. Although relief portions 23 provided on the outer movable plate 3 are not shown in FIGS. 7 and 8, they may be formed at the same time as molding or punching.
[0033]
Next, the second drive coil 6 is formed on the upper surface of the polyimide substrate 32. The formation of the second drive coil 6 is performed in the same manner as the first drive coil 9 by the manufacturing process shown in FIG. In each of the figures, a cross-sectional view taken along the line C-O'-D of FIG. 2 is shown.
[0034]
First, in the step (a), a thin film of, for example, aluminum as a highly conductive metal is formed on almost the entire surface of the polyimide substrate 32 with a thickness of about 2 μm by a vacuum film forming technique such as sputtering or copper by plating. Next, a resist is applied thereon, and on the upper surface of the outer movable plate 3, a first contact portion 6b for making an electrical connection with the first-layer drive coil 6a and the second-layer drive coil and a first contact portion 6b (not shown) A coil-shaped resist pattern is formed while leaving a portion of the resist corresponding to the two relay terminals 26A, 26A (see FIG. 2). Then, after etching the aluminum thin film using this as a mask, the resist is removed to form the first-layer drive coil 6a, the first contact portion 6b, and the second relay terminals 26A, 26A (not shown).
[0035]
Next, in the step (b), a first insulating layer 33a of photosensitive polyimide is formed on the first-layer driving coil 6a to a thickness of about 2 μm. In this case, on the first contact portion 6b, portions corresponding to the second relay terminals 26A, 26A (not shown), and second and third lead wires 25 (not shown) from the outer torsion bar 2 to the outer fixing portion 1. , 27, and the portions corresponding to the outer and inner electrode terminals 7A, 7A, 10A, 10A (see FIG. 2) on the outer fixed portion 1 (not shown), the first insulating layer 33a is formed. Is done. Further, in the same manner as in step (a), a thin film of aluminum or the like is formed to a thickness of about 2 μm on the entire surface of the polyimide substrate 32, and this is etched to form a second-layer drive coil 6c, a second contact portion 6d, and a not-shown illustration. , And the outer and inner electrode terminals 7A, 7A, 10A, 10A (see FIG. 2) not shown.
[0036]
Then, in the step (c), the photosensitive polyimide covering the second-layer drive coil 6c, the second contact part 6d, and the second and third lead wires 25 and 27 in the same manner as the step (b). Of the second insulating layer 33b is formed. Thereby, the outer movable portion 17 is formed.
[0037]
The inner movable portion 16 and the outer movable portion 17 thus formed are adhered in the direction of arrow Q in FIG. 2, and the inner movable portion 16 is fixed at the center of the outer movable plate 3 within the broken line frame P in FIG. Will be held. Further, as shown in FIG. 1, the first and second relay terminals 22A, 22A, 26A, 26A are wire-bonded with bonding wires W so that the first drive coil 9 can be energized. The static magnetic field generating means 18A to 19B are arranged outside the portion 1 with the opposite magnetic poles facing each other with the outer movable plate 3 and the inner movable plate 5 interposed therebetween. Thus, the planar actuator shown in FIG. 1 is completed.
[0038]
Further, the method of forming the second drive coil 6 on the plastic substrate 32 as described above is not limited. Wiring such as the second drive coil 6 is previously formed at a predetermined position of the plastic plate material 31 and is formed. The outer movable portion 17 provided with wiring such as the second drive coil 6 may be manufactured by punching.
[0039]
Further, as described above, each drive coil is not limited to one formed individually when forming each drive unit, and each drive coil may be formed after the inner drive unit 16 and the outer drive unit 17 are integrated. Good.
[0040]
Furthermore, the planar actuator of the present invention is not limited to the above-described electromagnetically driven actuator, may be an electrostatically driven actuator, and is not limited to the above-described optical scanner. Any actuator can be used as long as it is a planar actuator that rotates below.
[0041]
【The invention's effect】
As described above, according to the planar actuator of the present invention, the inner movable portion and the outer movable portion are formed of materials having different rigidities and are integrally formed, so that the inner movable plate and the outer movable plate have the same frequency. Driving can be performed at different resonance frequencies having large ratios. Therefore, when applied to an optical scanner, raster scanning of laser light can be easily performed by controlling the driving of the inner movable portion and the outer movable portion.
[0042]
In addition, when applied to an optical scanner, the movable plate can be stopped at a predetermined position with a small force by forming one of the inner and outer movable portions with a plastic material having a small rigidity. Can be rotated in a stepwise manner, and horizontal scanning of the laser beam becomes possible.
[0043]
Further, when the inner movable portion is formed of silicon and the outer movable portion is formed of plastic, the number of the inner movable portion formed from one silicon substrate increases because the shape of the inner movable portion is small, and the manufacturing cost is reduced. In addition, the outer movable part having a large shape can be easily manufactured by molding or punching out a plastic material, thereby reducing the manufacturing cost. Furthermore, the inner movable part and the outer movable part which are individually manufactured can be reduced. Since the parts are joined, the manufacturing yield of the final product is improved, and an inexpensive planar actuator can be provided.
[0044]
Furthermore, when the inner movable portion is formed of silicon and the outer movable portion is formed of plastic, deformation such as warpage of the inner movable plate can be suppressed, and when applied to an optical scanner, scanning accuracy of light is improved, Further, since the outer torsion bar is made of plastic, durability against breakage and the like can be improved.
[0045]
Further, since the two-dimensional scanning type planar actuator has a composite structure of silicon and plastic, vibration resistance and impact resistance are improved, and the production yield is improved, as compared with the case where the two-dimensional scanning type actuator is made of only silicon material.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic configuration of an embodiment of a planar actuator according to the present invention.
FIG. 2 is an exploded perspective view of FIG.
FIG. 3 is a center sectional view showing another method for integrating the inner movable portion and the outer movable portion.
FIG. 4 is a central cross-sectional view showing another example of the configuration of the relief portion formed in the outer movable portion.
FIG. 5 is an explanatory view showing a manufacturing step of a drive coil among manufacturing steps of an inner movable portion.
FIG. 6 is an explanatory view showing an etching step of a silicon substrate in a manufacturing step of the inner movable portion.
FIG. 7 is an explanatory view showing a method of manufacturing the outer movable portion by die molding.
FIG. 8 is an explanatory view showing another manufacturing method of FIG. 6;
FIG. 9 is an explanatory view showing a manufacturing step of a drive coil among manufacturing steps of the outer movable portion.
FIG. 10 is an exploded perspective view showing the structure of a conventional two-dimensional scanning type planar actuator.
[Explanation of symbols]
1: Outside fixed part
2 ... outside torsion bar
3. Outside movable plate
4: Inside torsion bar
5 inside movable plate
6, 9 ... drive coil
16 Inside movable part
17 ... Outside movable part
18A to 19B: Static magnetic field generating means
20 ... inner fixed part
22A, 26A ... relay terminal
23 ... escape

Claims (10)

An outer movable portion provided with an outer movable plate rotatably supported by an outer torsion bar on an outer fixed portion,
An inner movable portion provided with an inner movable plate pivotally supported on an inner fixed portion by an inner torsion bar,
A driving unit for driving each of the movable plates, wherein the outer movable portion and the inner movable portion are formed of materials having different rigidities, and an axial direction of the outer torsion bar is orthogonal to an axial direction of the inner torsion bar. Wherein the inner movable portion is fixed to an outer movable plate of the outer movable portion. One of the outer movable portion and the inner movable portion is formed using silicon as a main material for determining rigidity, and the other is formed using a material having lower rigidity than the silicon as a main material for determining rigidity. The planar actuator according to claim 1, wherein the actuator is configured. The planar actuator according to claim 2, wherein the inner movable portion is formed of silicon, and the outer movable portion is formed of a material having lower rigidity than silicon. The planar actuator according to claim 3, wherein the outer movable portion is formed of plastic. The planar type actuator according to any one of claims 1 to 4, wherein the inner movable portion is configured to be bonded to an upper surface of the outer movable plate. The planar type actuator according to any one of claims 1 to 4, wherein the inner movable portion is configured to be fitted into the outer movable plate. 7. The planar type according to claim 1, wherein a relief portion is provided at a portion of the outer movable plate corresponding to the inner movable plate so that the inner movable plate does not contact the outer movable plate when rotating. Actuator. The driving means includes a driving coil laid on each of the movable plates, and a static magnetic field generating means for applying a static magnetic field to each of the driving coils, and an electromagnetic force generated by applying a current to each of the driving coils The planar actuator according to any one of claims 1 to 7, wherein each of the movable plates is driven. 9. The planar type according to claim 8, wherein the drive coil laid on the inner movable plate is drawn out from a portion near the rotation axis of the outer movable plate to the outside via the outer torsion bar. Actuator. A relay terminal of a drive coil laid on the inner movable plate is provided on the inner fixed portion and the outer movable plate near a rotation axis of the outer movable plate, and each of the relay terminals is wire-bonded. The planar actuator according to claim 9, wherein

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