JP2009216999A - Optical deflector and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical defector in which the positional shift of a magnet and the bend of a mirror are suppressed, and also to provide a method of manufacturing the optical deflector. <P>SOLUTION: The optical deflector 1 of the present embodiment has: a mirror 2 which is so composed to be turnable around a predetermined axis and has a reflection face; a magnet 22 arranged on the back face of the reflection face of the mirror; and an adhesive 23 which bonds the back face of the mirror and the side face of the magnet. For example, the adhesive 23 is partially provided at a plurality of points on the outer periphery of the magnet 22, and provided at a point symmetry with respect to the center of the outer profile of the magnet 22. Alternatively, the adhesive 23 may be provided in a frame shape to enclose the outer periphery of the magnet 22. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical deflector using MEMS (Micro Electro Mechanical System) technology and a driving method thereof.

  In recent years, development of microactuators using MEMS technology has been active. For example, an optical deflector including a mirror supported to be torsionally rotated by a pair of elastic support portions (torsion bars) has been developed as a device capable of forming an image display device with a simple configuration.

  As a method for driving such a mirror, a method using electrostatic attraction, a method using electromagnetic force, and a method using a piezoelectric element are mainly cited.

Among these, in an optical deflector using an electromagnetic force, a magnet for applying a driving force for rotating the mirror is joined to the back side of the reflecting surface of the mirror (see Patent Document 1). By applying an adhesive between the mirror and the magnet, the mirror and the magnet are joined.
JP 2005-169553 A

  However, when the thickness of the adhesive is not uniform, the magnet may be tilted. Since the inclination of the magnet affects the magnetic field, as a result, the rotation of the mirror is affected. Further, even if the thickness of the adhesive is uniform, there is a problem that the mirror is bent due to the shrinkage when the adhesive is cured, and the mirror is bent.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide an optical deflector capable of suppressing displacement of a magnet and bending of a mirror and a method for manufacturing the same.

  In order to achieve the above object, an optical deflector of the present invention includes a mirror having a reflective surface configured to be rotatable along a predetermined axis, a magnet disposed on the back surface of the reflective surface of the mirror, and And an adhesive that joins the back surface of the mirror and the side surface of the magnet.

  According to the said structure, the back surface of a mirror and the side surface of a magnet are joined by an adhesive agent. As described above, in the present invention, since no adhesive is provided between the magnet and the mirror, the inclination and displacement of the magnet due to the adhesive are prevented. Moreover, compared with the case where an adhesive is applied to the entire surface between the magnet and the mirror, the stress generated during curing is reduced, and the bending of the mirror is suppressed.

  For example, the adhesive is partially provided at a plurality of locations on the outer edge of the magnet. As a result, the amount of the adhesive can be reduced, and the stress generated when the adhesive is cured is further reduced. In this case, the adhesive is preferably provided point-symmetrically with respect to the center of the outer shape of the magnet. Thereby, since the force resulting from the shrinkage at the time of curing of the adhesive is generated point-symmetrically with respect to the center of the magnet, the displacement of the magnet due to the force is prevented.

  Alternatively, the adhesive is provided in a frame shape so as to surround the outer edge of the magnet. Thereby, the adhesive force between a mirror and a magnet is raised compared with the case where an adhesive agent is partially provided on the outer edge of a magnet.

  Preferably, a groove for accommodating the adhesive is formed at a position corresponding to the outer edge of the magnet on the back surface of the mirror. Thereby, since the adhesion area of the back surface of a mirror and a magnet increases, the adhesive force between a mirror and a magnet is raised.

  In order to achieve the above object, the method of manufacturing an optical deflector according to the present invention includes a step of placing a magnet on the back surface of the reflecting surface of the mirror, and applying an adhesive on the back surface of the mirror at the outer edge of the magnet. And joining the back surface of the mirror and the side surface of the magnet.

  In the said structure, after mounting a magnet on the back surface of the reflective surface of a mirror, an adhesive agent is apply | coated on the back surface of the mirror in the outer edge of a magnet. Therefore, the magnet is joined to the reflecting surface of the mirror while preventing the tilt and displacement of the magnet due to the thickness of the adhesive. Moreover, compared with the case where an adhesive is applied to the entire surface between the magnet and the mirror, the stress generated during curing is reduced, and the bending of the mirror is suppressed.

  For example, the optical deflector manufacturing method of the present invention includes a step of forming a mask having a predetermined pattern on both sides of the substrate, a step of processing the substrate into a mirror shape by etching the substrate using the mask, A step of placing a magnet on the back surface of the mirror surface of the substrate, and a step of applying an adhesive on the back surface of the substrate at the outer edge of the magnet to join the back surface of the substrate and the side surface of the magnet.

  For example, a groove may be formed at a position corresponding to the outer edge of the magnet on the back surface of the substrate simultaneously with the step of processing the substrate into a mirror shape. Due to the presence of this groove, the adhesion area between the back surface of the substrate and the magnet is increased, so that the adhesion force between the substrate and the magnet is enhanced.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a plan view showing the configuration of the optical deflector according to the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG.

  The optical deflector 1 includes a movable plate 11, a support frame 12, and a pair of elastic support portions 13 that support the movable plate 11 so as to be torsionally rotatable with respect to the support frame 12. The movable plate 11, the support frame 12, and the elastic support portion 13 are integrally formed, for example, by etching a silicon substrate. A reflective film 21 is formed on the surface of the movable plate 11. Thereby, the mirror 2 including the movable plate 11 and the reflective film 21 is configured.

  A magnet 22 is joined to the back surface of the movable plate 11. The magnet 22 is magnetized in a direction orthogonal to the axis X that is the rotation center axis of the movable plate 11 when the movable plate 11 is viewed in plan. That is, the magnet 22 has a pair of magnetic poles that are opposed to each other via the axis X and have different polarities. The support frame 12 is joined to the holder 50, and a coil 51 for driving the movable plate 11 is disposed on the holder 50.

  In the oscillating mirror 1, a periodically changing current (AC) is supplied to the coil 51. As a result, the coil 51 alternately generates a magnetic field directed upward (movable plate 11 side) and a magnetic field directed downward. As a result, one of the pair of magnetic poles of the magnet 22 approaches the coil 51 and the other magnetic pole moves away, and the movable plate 11 rotates around the X axis while twisting and deforming the elastic support portion 13. Be moved.

  FIG. 3 is a rear view of the movable plate 11. FIG. 4 is a cross-sectional view showing how the movable plate 11 and the magnet 22 are joined.

  As shown in FIG. 4, in this embodiment, an adhesive 23 is applied to the side surface of the magnet 22, and thereby the back surface of the movable plate 11 and the side surface of the magnet 22 are joined. As the adhesive 23, various adhesives such as a thermosetting adhesive and an ultraviolet curable adhesive can be used.

  Further, in the present embodiment, the adhesive 23 is applied to a plurality of portions, not the entire outer edge of the magnet 22. In this case, it is preferable to provide the adhesive 23 symmetrically with respect to the center of the outer shape (excluding thickness) of the magnet 22. FIG. 3 shows an example in which adhesives 23 are provided at the four corners of the magnet 22, for example.

  Next, a method for manufacturing the optical deflector 1 according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 5, for example, a substrate 10 made of silicon is prepared. Then, as shown in FIG. 6, masks 31 and 32 made of silicon oxide are formed on both surfaces of the substrate 10 by thermal oxidation.

  Next, as shown in FIG. 7, a resist 41 is formed on the mask 31 on the surface side of the substrate 10. The resist may be positive or negative. Subsequently, as shown in FIG. 8, a resist 42 is formed on the mask 32 on the back surface side of the substrate 10.

  Next, as shown in FIG. 9, the resist 42 on the back surface side of the substrate 10 is exposed and developed to form a predetermined opening pattern P <b> 2 in the resist 42. The opening pattern P2 is a pattern that opens an area other than the movable plate 11, the support frame 12, and the elastic support portion 13, for example.

  Next, as shown in FIG. 10, the mask 32 on the back surface side is etched using the resist 42 as a mask. Thereby, the opening pattern P2 of the resist 42 is transferred to the mask 32. For example, buffered hydrofluoric acid (BHF) is used for etching the mask 32.

  Next, as shown in FIG. 11, the resists 41 and 42 on both sides of the substrate are removed. For removing the resists 41 and 42, sulfuric acid washing or ashing is used.

  Next, as shown in FIG. 12, a resist 43 is formed again on the back side of the substrate 10. Further, as shown in FIG. 13, a resist 44 is formed again on the surface side of the substrate 10.

  Next, as shown in FIG. 14, the resist 44 on the surface side of the substrate 10 is exposed and developed to form a predetermined opening pattern P <b> 1 in the resist 44. The opening pattern P1 is, for example, the same pattern as the opening pattern P2.

  Next, as shown in FIG. 15, the mask 31 on the surface side is etched using the resist 44 as a mask. Thereby, the opening pattern P1 of the resist 44 is transferred to the mask 31. For the etching of the mask 31, for example, buffered hydrofluoric acid (BHF) is used.

  Next, as shown in FIG. 16, the resists 43 and 44 on both surfaces of the substrate are removed. For removing the resists 43 and 44, sulfuric acid cleaning or ashing is used.

  Next, as shown in FIG. 17, the substrate 10 is etched using masks 31 and 32. Thereby, a through-hole is formed in the substrate 10, and a pattern of the movable plate 11, the support frame 12, and the elastic support portion 13 is formed. For the etching of the substrate 10, either dry etching or wet etching can be applied. For example, wet etching using KOH is used.

  Next, as shown in FIG. 18, after removing the masks 31 and 32, a reflective film 21 is formed on the movable plate 11 by forming a metal film on the surface of the substrate 10 and patterning it. Examples of the method for forming the metal film include vacuum deposition, sputtering, electroplating, electroless plating, and metal foil bonding. Note that the mask 31 and the mask 32 may be left without being removed.

  Next, as shown in FIG. 19, the magnet 22 is placed on the back surface of the movable plate 11. Subsequently, as shown in FIG. 20, the adhesive 23 is applied on the back surface of the movable plate 11 at the outer edge of the magnet 22, and the adhesive 23 is cured, whereby the side surface of the magnet 22 and the back surface of the movable plate 11 are bonded. Join.

  As the subsequent steps, the optical deflector 1 is mounted by attaching the structure including the movable plate 11, the support frame 12, and the elastic support portion 13 manufactured using a single substrate in this manner to the holder 50. Manufactured.

  In the optical deflector 1 and the manufacturing method thereof according to the above embodiment, the back surface of the movable plate 11 and the side surface of the magnet 22 are joined by the adhesive 23. Thus, in this embodiment, since the adhesive 23 is not provided between the magnet 22 and the movable plate 11, the inclination and displacement of the magnet due to the adhesive 23 are prevented. Moreover, compared with the case where an adhesive is applied to the entire surface between the magnet 22 and the movable plate 11, the stress generated during curing is reduced, and the bending of the movable plate 11 is suppressed.

  In the present embodiment, the adhesive 23 is partially provided on the outer edge of the magnet 22 at a plurality of locations. As a result, the amount of the adhesive 23 can be reduced, and the stress generated when the adhesive 23 is cured is further reduced. In this case, the adhesive 23 is preferably provided point-symmetrically with respect to the center of the outer shape of the magnet 22. Thereby, since the force resulting from the shrinkage at the time of hardening of the adhesive 23 is generated point-symmetrically with respect to the center of the magnet, the displacement of the magnet due to the force is prevented.

(Second Embodiment)
FIG. 21 is a rear view of the movable plate 11 of the optical deflector 1 according to the second embodiment. In the second embodiment, the adhesive 23 has the same configuration as that of the first embodiment except that the adhesive 23 is provided in a frame shape so as to surround the outer edge of the magnet 22.

  As described above, the adhesive 23 is provided in a frame shape so as to surround the outer edge of the magnet 22, so that the movable plate 11 and the magnet are compared with the case where the adhesive is partially provided on the outer edge of the magnet 22. Adhesive strength between the two is increased.

(Third embodiment)
FIG. 22 is a cross-sectional view showing how the movable plate 11 and the magnet 22 are joined in the optical deflector 1 according to the third embodiment.

  The third embodiment has the same configuration as that of the first embodiment except that a groove 14 for accommodating the adhesive 23 is formed at a position corresponding to the outer edge of the magnet 22 on the back surface of the movable plate 11. . The adhesive 23 may be partially formed at a position corresponding to the outer edge of the magnet 22 or may be formed in a frame shape.

  The groove 14 can be formed simultaneously with the processing of the substrate 10. With reference to FIGS. 23 and 24, a method of forming the groove 14 will be described. 23 and 24, (A) is a cross-sectional view, (B) is a front view, and (C) is a back view.

  First, as shown in FIG. 23, masks 31 and 32 having desired patterns are formed on both surfaces of the substrate 10 through the same process as in the first embodiment. At this time, an opening pattern P2 ′ for forming a groove is added to the opening pattern P2 of the mask 32 on the back side of the substrate 10. FIG. 23 shows an example in which the opening pattern P2 ′ is formed at eight points corresponding to the outer edge of the magnet 22, but the present invention is not limited to this.

  Next, as shown in FIG. 24, the substrate 10 is etched using the masks 31 and 32. Thereby, a through-hole is formed in the substrate 10, and a pattern of the movable plate 11, the support frame 12, and the elastic support portion 13 is formed. In addition, since the opening pattern P2 ′ is formed only on the back surface of the substrate 10, a groove 14 is formed on the back surface of the substrate 10 instead of the through hole. For the etching of the substrate 10, either dry etching or wet etching can be applied. For example, wet etching using KOH is used.

  As the subsequent steps, the optical deflector 1 is manufactured through the same steps as in the first embodiment.

  In the present embodiment, the groove 14 is formed at a position corresponding to the outer edge of the magnet 22 on the back surface of the movable plate 11, thereby bonding the movable plate 11 and the adhesive, and thus the movable plate 11 and the magnet 22. And the adhesion between the mirror and the magnet is increased. Further, by using the groove 14 as an alignment mark when the magnet 22 is arranged, the magnet 22 can be placed at a desired position with high accuracy.

(Fourth embodiment)
As an application example of the optical deflector 1 according to the present embodiment, a projection type display device will be described. FIG. 25 is a diagram illustrating a schematic configuration of a projection type display device. The optical scanning device shown in FIG. 25 uses the optical deflector 1 shown in FIG. 1 as a horizontal scanning mirror.

  The optical scanning device shown in FIG. 25 includes a laser light source 101, a dichroic mirror 102, a photodiode 103, and a vertical mirror 104 in addition to the optical deflector 1.

  The laser light source 101 includes a red laser light source 101R that emits red laser light, a blue laser light source 101B that emits blue laser light, and a green laser light source 101G that emits green laser light. However, laser light sources of two colors or less or four colors or more may be used.

  The dichroic mirror 102 includes a dichroic mirror 102R that reflects red laser light from the red laser light source 101R, a dichroic mirror 102B that reflects blue laser light and transmits red laser light, and reflects green laser light and blue laser light and red. A dichroic mirror 102G that transmits laser light. By these three types of dichroic mirrors 102, the combined light of red laser light, blue laser light, and green laser light is incident on the vibrating mirror 1.

  The photodiode 103 detects the amounts of red laser light, green laser light, and blue laser light that are transmitted without being reflected by the dichroic mirrors 102R, 102G, and 102B.

  The optical deflector 1 scans the laser beam sent from the dichroic mirror 102 in the horizontal direction (the vertical direction of the axis X). As described above, the optical deflector 1 is a resonant mirror formed by MEMS.

  The vertical mirror 104 scans the laser beam reflected by the optical deflector 1 in the vertical direction. The vertical mirror 104 is configured by a galvanometer mirror, for example. A galvanometer mirror is a deflector in which a mirror is provided with an axis so that the rotation angle of the mirror can be changed according to electric vibration. An image is displayed by horizontal scanning of the laser light by the optical deflector 1 and vertical scanning of the laser light by the vertical mirror 104.

  The optical scanning device according to the present embodiment further drives a laser driving unit 110 that drives the laser light source 101 and the optical deflector 1 as a drive control system for the laser light source 101, the vibrating mirror 1, and the vertical mirror 104. It has a horizontal mirror driving means 111, a vertical mirror driving means 112 for driving the vertical mirror 104, a control means 113 for controlling the overall operation, and a storage means 114.

  The control means 113 is based on image information sent from various video sources 115 such as a personal computer or a mobile phone, and displays these images by means of a laser drive means 110, a horizontal mirror drive means 111, a vertical mirror drive means. The operation of 112 is controlled.

  The storage unit 114 includes, for example, a ROM that stores various programs, a RAM that stores variables, and the like, and a nonvolatile memory.

  By applying the optical deflector 1 according to the present embodiment to a display device, a display device with good display performance can be realized.

The present invention is not limited to the description of the above embodiment.
For example, the movable plate 11 may be a polygon other than a circle. Further, in the present embodiment, the movable plate 11 of a type that is driven in a one-dimensional one degree of freedom is illustrated, but the movable plate 11 may be a type of a movable plate 11 that is driven in two dimensions, and is driven in a one-dimensional two degrees of freedom. The type of movable plate 11 may be used. When a two-dimensional driving type oscillating mirror is used, the vertical mirror 104 is not necessary.
The optical deflector 1 can be applied to a laser printer or the like other than the display device.
In addition, various modifications can be made without departing from the scope of the present invention.

It is a top view of the optical deflector which concerns on 1st Embodiment. It is sectional drawing of the II-II line | wire of FIG. It is a reverse view of a movable plate. FIG. 6 is a cross-sectional view in the vicinity of the joint between the movable plate and the magnet 22. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. It is process sectional drawing which shows the manufacturing method of the optical deflector which concerns on 1st Embodiment. In the optical deflector which concerns on 2nd Embodiment, it is a reverse view of the movable plate 11. FIG. It is sectional drawing of the vicinity of joining of the magnet 22 and the movable plate 11 in the optical deflector which concerns on 3rd Embodiment. It is process drawing which shows the manufacturing method of the optical deflector which concerns on 3rd Embodiment. It is process drawing which shows the manufacturing method of the optical deflector which concerns on 3rd Embodiment. It is a schematic block diagram of the display apparatus using the optical deflector based on 4th Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical deflector, 2 ... Mirror, 10 ... Board | substrate, 11 ... Movable plate, 12 ... Support frame, 13 ... Elastic support part, 14 ... Groove, 50 ... Holder, 21 ... Reflective film, 22 ... Magnet, 23 ... Adhesion Agent, 31, 32 ... Mask, 41, 42, 43, 44 ... Resist, 50 ... Holder, 51 ... Coil, 100 ... Display device, 101 ... Laser light source, 101R ... Red laser light source, 101G ... Green laser light source, 101B ... Blue laser light source, 102, 102R, 102G, 102B ... Dichroic mirror, 103, 103R, 103G, 103B ... Photodiode, 104 ... Vertical mirror, 110 ... Laser drive means, 111 ... Horizontal mirror drive means, 112 ... Vertical mirror drive means , 113 ... control means, 114 ... storage means, 115 ... video source, P1, P2 ... opening pattern

Claims (8)

A mirror having a reflecting surface, configured to be rotatable along a predetermined axis;
A magnet disposed on the back surface of the reflecting surface of the mirror;
An adhesive that joins the back surface of the mirror and the side surface of the magnet;
An optical deflector. The adhesive is provided at a plurality of locations partially on the outer edge of the magnet.
The optical deflector according to claim 1. The adhesive is provided point-symmetrically with respect to the center of the outer shape of the magnet.
The optical deflector according to claim 2. The adhesive is provided in a frame shape so as to surround the outer edge of the magnet.
The optical deflector according to claim 1. A groove for accommodating the adhesive is formed at a position corresponding to the outer edge of the magnet on the back surface of the mirror.
The optical deflector according to claim 1. A step of placing a magnet on the back surface of the reflecting surface of the mirror;
Applying an adhesive on the back surface of the mirror at the outer edge of the magnet, and joining the back surface of the mirror and the side surface of the magnet;
The manufacturing method of the optical deflector which has. Forming a mask having a predetermined pattern on both sides of the substrate;
Etching the substrate using the mask to process the substrate into a mirror shape;
Placing a magnet on the back surface of the mirror surface of the substrate;
Applying an adhesive on the back surface of the substrate at the outer edge of the magnet, and joining the back surface of the substrate and the side surface of the magnet;
The manufacturing method of the optical deflector which has. Simultaneously with the step of processing the substrate into a mirror shape, a groove is formed on the back surface of the substrate and at a position corresponding to the outer edge of the magnet.
The manufacturing method of the optical deflector of Claim 7.

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