WO2005026817A1

WO2005026817A1 - Optical scanner device

Info

Publication number: WO2005026817A1
Application number: PCT/JP2004/013222
Authority: WO
Inventors: Norihiro Asada
Original assignee: Mems Technology Co., Ltd
Priority date: 2003-09-11
Filing date: 2004-09-10
Publication date: 2005-03-24
Also published as: JP2005084571A

Abstract

In an optical scanner device, a structure body with an integrated structure where a flat plate-like movable section (4) is supported inside a stationary section (2) by torsion beams (3) is formed of a monocrystal silicon and a mirror is provided on the movable section (4). A hard magnetic body (6) magnetized in the thickness direction of the movable section is provided on the movable section (4), and an electromagnet (20) with a letter U-shaped core is provided so as to face the hard magnetic body (6). The optical scanner device uses the structure above to deflect and scan incident light, and as a result, the device is easily reduced in size, has durability, and can perform large amplification.

Description

Specification

Optical scanner device

Technical field

The present invention relates to an optical scanner device for deflecting and scanning incident light, and more particularly to driving a movable portion thereof. Background art

[0002] As a conventional technique for deflecting and scanning light, there is a polygon mirror widely used in printers and the like. The polygon mirror is a mirror whose polygonal side surface is rotated by a spindle motor. The mirror is irradiated with a laser beam or the like, and the laser beam or the like irradiated by rotating the polygon mirror is sequentially deflected and scanned. However, the polygon mirror requires relatively large power for the spindle motor, and the noise peculiar to the motor bearing is large.

[0003] A galvano mirror is often used for applications other than a printer, such as a laser marker, a laser processing machine, and a laser microscope. This galvanometer mirror is also driven by a motor, and it is possible to keep the mirror stationary. However, since the mirrors are assembled with large mechanical parts, the size of the device becomes large, and a large amount of power is required to drive it.

[0004] Under such circumstances, an optical scanner using a micromachining technology that is compact and consumes less power has been proposed.

[0005] There are various driving methods for the optical scanner using the micromachining technology. However, the electromagnetic method can increase the scanning amplitude as compared with the electrostatic-piezoelectric method. ing.

[0006] Examples of this are those described in Patent Literature 1, Patent Literature 2, and Patent Literature 3 below. In the structure described in Patent Document 1, as shown in FIG. 5, a structure 50 is formed of single-crystal silicon, and a coil 53 is formed on a movable portion 52 supported by a torsion beam (a beam capable of torsion operation) 51. Mirror 54 is laid. The principle of operation is that a current flows through the coil 53 in the magnetic field generated by the external permanent magnet 55 to generate Lorentz force and obtain driving force. This drive system is an electromagnetic actuator Is called the moving coil system. As shown in FIG. 6, the structure described in Patent Document 2 has a structure 60 made of single-crystal silicon, a mirror 62 and a soft magnetic material 63 laid on a movable portion 61, and a soft magnetic material 63 on the outside. The electromagnet 64 is fixed opposite to one side, and the movable portion 61 is driven by the attraction force caused by flowing a current through the electromagnetic stone 64. This method is similar to the moving magnet method in the classification of electromagnetic actuators. The one described in Patent Document 3 has a structure 70 formed of a semiconductor, a movable part 71 provided with a magnetic film 72 magnetized in a direction perpendicular to the film surface, and two externally wound winding directions opposite to each other. The coils 73 and 74 are fixed, and the movable portion 71 is driven by a repulsive force and an attractive force generated by a magnetic force generated in each coil by flowing a current through the coils 73 and 74 and a magnetic force of the magnetic film 72. This method is a modification of the moving magnet method.

Patent Document 1: JP-A-7-175005 (Patent No. 2722314)

Patent Document 2: JP-A-2002-311372

Patent Document 3: JP-A-2002-189187

Disclosure of the invention

Problems to be solved by the invention

[0007] In the method described in Patent Document 1, since the lead wire to the coil is laid on the torsion beam, the wire is twisted according to the torsion of the beam, which may cause a problem in durability. In addition, it is difficult to reduce the resistance of a coil made of a thin film.

I have to consider. Assuming that the coil is formed, there is a problem that miniaturization is difficult.

[0008] The method described in Patent Document 2 can solve the above-mentioned problem in the moving coil method described in Patent Document 1, but when driven only by the suction force, a force is applied to the end of the movable portion. As a result, the movable part is twisted, but the whole movable part is pulled toward the electromagnet, and the mirror position is likely to shift, especially when a large force is applied due to large amplitude. Is a problem. In the method described in Patent Document 3, since the movable portion is driven by the repulsive force and the attractive force, the entire movable portion in the method described in Patent Document 2 is pulled toward the electromagnet, and the position of the mirror is shifted. Although the problem can be solved, Since the coil is air-core, a large current is required for driving and two coils with different winding directions are required.

[0009] The present invention has been made under such circumstances, and it is an object of the present invention to provide an optical scanner device that can be easily miniaturized, is durable, and has a large amplitude. .

Means for solving the problem

[0010] In order to solve the above-mentioned problems, in the present invention, the optical scanner device is configured as described in the following (1) to (4).

(1) An optical scanner device in which an integrated structure in which a flat movable portion is supported by a torsion beam inside a fixed portion is made of monocrystalline silicon, and the movable portion is provided with a mirror, A hard magnetic body magnetized in the thickness direction of the movable part, provided on the flat movable part, and a u-shaped core-equipped electromagnet disposed opposite to the hard magnetic body,

An optical scanner device comprising:

(2) The optical scanner according to the above (1),

The electromagnet with a U-shaped core is divided into a total of three parts, one point at each end of the core and one point at the center of the core. An optical scanner device comprising an electromagnet with a U-shaped core formed by insert molding in a vessel and joining a coil-wound portion, which is a central portion of the core, to both end portions of the core.

(3) In the optical scanner device according to (1) or (2),

An optical scanner device wherein the hard magnetic body is formed on the movable portion by plating.

(4) In the optical scanner device according to (1) or (2),

An optical scanner device wherein the hard magnetic material is formed on the movable portion by a thin film forming method such as sputtering or vacuum deposition.

The invention's effect

[0015] According to the present invention, it is not necessary to form a coil in the movable part, so that miniaturization is easy, and since there is no coil in the movable part, the lead wire of the coil is not twisted by the torsion beam part, and the durability is high. Yes, large amplitude is possible because it is excited by an electromagnet with a U-shaped core.

Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a structure according to a first embodiment. FIG. 2 is a diagram showing the operating principle of Embodiment 1.

FIG. 3 is a graph showing characteristics of Example 1.

FIG. 4 is a diagram showing how to assemble in Example 1

FIG. 5 is a diagram showing an optical scanner device described in Patent Document 1

FIG. 6 is a diagram showing an optical scanner device described in Patent Document 2

FIG. 7 is a diagram showing an optical scanner device described in Patent Document 3

Explanation of symbols

[0017] 1 Structure

2 Fixed part

3 Torsion beam

4 Moving parts

5 mirror

6 Hard magnetic material

20 U-shaped cored electromagnet

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to embodiments of an optical scanner device.

Example 1

FIG. 1 is a diagram illustrating a configuration of a structure 1 of the “optical scanner device” according to the first embodiment. As shown in the figure, fixed part 2, movable part 4 and fixed part 2 and movable part 4 are connected by a single-crystal silicon plate.

The torsion beam 3 to be puttered with high precision using semiconductor photolithography technology. In addition, each figure is exaggerated in size for convenience of explanation, and, for example, the movable part 4 is several millimeters in size.

[0020] Further, in the portion where the hard magnetic material 6 (film magnet, see FIG. 2) is provided in advance in the puttered region, there is a difference in the shape. Arrange.

Then, as shown in FIG. 2, a film magnet of the hard magnetic material 6 is formed on one surface of the movable portion 4 where the film is formed. [0022] The film magnet has a high coercive force such as a rare earth samarium cobalt-based material formed by sputtering, rare earth-Fe-B, Fe-Pt, or a cobalt-based material used in magnetic storage devices. Use material. For the film formation method, a chemical method or a physical method is selected in consideration of film characteristics and cost.

As shown in FIG. 2, an electromagnet 20 with a U-shaped core is arranged outside the structure 1 so as to face the hard magnetic material 6. The electromagnet 20 is an electromagnet with a U-shaped core 7 designed to have opposite polarities at both ends of the movable section 4.

In the electromagnet 20, the core 7 is made of a soft magnetic material, and is integrally formed with the single crystal silicon structure 1 together with the knockout 40 as shown in FIG. It is desirable that the magnetization of the hard magnetic material 6 be performed immediately before assembly, but it is also possible to perform magnetization after assembly.

[0025] If an electromagnet with a U-shaped core is used, only one coil is required for the electromagnet, and both cost and process can be reduced. However, it is difficult to attach a bobbin coil to a U-shaped core. To make this easier, the U-shaped core is divided into three points, and rod-shaped cores are created and assembled, thereby reducing costs and processes.

[0026] More specifically, as shown in Fig. 4, two cores 41 that do not have a bobbin-wound coil mounted on a plastic package 40 are insert-molded in advance, and a core 42 with a bobbin-wound coil mounted on the core is also used as a core. It is assembled into the plastic package 40 so as to be joined to the end of 41.

In the case of an optical scanner device using single crystal silicon, a movable portion and a torsion beam are often designed and used as a resonator in order to obtain a large amplitude with a small amount of marking energy. When used as a resonator, the material frequency of single crystal silicon is extremely stable, so the resonance frequency is determined only by the shape. Although the torsional first-order resonance mode is used, it goes without saying that a higher-order mode that is not the target must be designed to be excluded by simulation or the like.

When a current is applied to the electromagnet 20 of the optical scanner device thus assembled, as shown in FIG. 2, an attractive force and a repulsive force are applied to both ends of the movable portion 4, so that the torsion beam 3 is used as a rotation axis. Therefore, the movable part 4 is tilted in a well-balanced manner. When the application of the current is stopped, the torsion beam 3 returns to the original position by the restoring force. If the applied current is an alternating current as shown in FIG. 3, the motion according to the frequency of the alternating current will be repeated. When the value of the applied current is constant, the amplitude of the movable part becomes maximum at the resonance frequency and decreases as the distance from the resonance frequency increases, as shown in Fig. 3 (b). When the frequency is constant, the amplitude increases in proportion to the value of the applied current, as shown in Fig. 3 (c).

In the configuration of the present embodiment, the coercive force of the film magnet (permanent magnet) provided in the movable portion is slightly smaller.

However, since the magnetic force generated by the cored electromagnet can be increased (the magnetic flux density is 1000 to 10,000 times that of an air-core coil), it is easy to obtain a large amplitude. Also, since the electromagnet exists outside the single-crystal silicon structure, the generated heat does not affect the single-crystal silicon structure. In the optical scanner device described in Patent Document 1, the heat generated in the coil of the movable portion causes the temperature of the material of the movable portion to rise, and the material itself undergoes thermal expansion, so that the stress applied to the torsion beam changes, and the resonance frequency decreases. It deviates from the design value. In the device of the present embodiment, such a problem does not occur because there is no heating element in the movable part.

[0031] As described above, in the present embodiment, it is not necessary to form a coil in the movable part, so that it is easy to reduce the size, and since there is no coil in the movable part, the introduction line of the coil is a torsion beam part. Durable without twisting. Also, since the excitation is performed by an electromagnet with a U-shaped core, the movable part can be tilted in a well-balanced manner, the magnetic force can be increased, and a large amplitude is possible.

[0032] Furthermore, with one electromagnet with a U-shaped core, the magnetic force of the required reverse polarity is obtained at both ends of the movable portion, and the cost and process of manufacturing the electromagnet can be reduced. In addition, since the core of the electromagnet is divided into three points and combined by knocking, bobbin-wound coils can be easily mounted on the U-shaped core, reducing manufacturing costs and processes. it can. Parts with an I-shaped core and a bobbin-wound coil are used in wristwatches, etc., and can be obtained at low cost.

[0033] (deformation)

In the above-described embodiment, the hard magnetic body may be provided only at the positions opposed to the core 41 at both ends of the force movable body in which the hard magnetic body is provided over the entire surface of the flat movable body. Further, the hard magnetic material may be provided on the same side as the mirror 5.

Claims

The scope of the claims

[1] An optical scanner device in which an integrated structure in which a flat movable portion is supported by a torsion beam inside a fixed portion is made of single crystal silicon and a mirror is provided in the movable portion, A hard magnetic material magnetized in the thickness direction of the movable portion, provided on the movable portion, and an electromagnet with a u-shaped core disposed opposite to the hard magnetic material,

An optical scanner device comprising:

[2] The optical scanner device according to claim 1,

The electromagnet with a U-shaped core is divided into a total of three parts, one at each end of the core and one at the center of the core. An optical scanner having a U-shaped core formed by insert-molding a core in a vessel, and joining a coil-wound portion, which is a central portion of the core, to both end portions of the core. .

[3] The optical scanner device according to claim 1 or 2,

The optical scanner device, wherein the hard magnetic body is formed on the movable portion by plating.

[4] The optical scanner device according to claim 1 or 2,

The optical scanner device, wherein the hard magnetic material is formed on the movable part by a thin film forming method such as sputtering or vacuum deposition.