JP2012027425A - Mirror structure and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror structure which has a mirror main body having a reinforced part and good accuracy and productivity and is obtained by good yield.SOLUTION: A mirror structure 10 has (A) a mirror main body 22 and a mirror 20 having a light reflection layer 21 provided on the mirror main body 22, (B) a mirror supporting part 50 supporting the mirror 20 and (C) a holding part 40 for holding the mirror holding part 50. The respective mirror holding part 50 is made from an actuator with a meander structure having an inflection point. The respective mirror holding part 50 is connected to the mirror 20 at the edge portion of the mirror 20 on which virtual lines orthogonal to the rotation axis AX of the mirror 20 cross each other. On the rear surface of the mirror main body 22, there is provided a reinforcement part 30.

Description

  The present invention relates to a mirror structure and a manufacturing method thereof, and more specifically, to a mirror structure using a so-called MEMS technology and a manufacturing method thereof.

  In recent years, development of a mirror structure using a micro electro mechanical system (MEMS), which is a microfabrication technology applying semiconductor device manufacturing technology, has been actively promoted. Such a mirror structure can be manufactured collectively on a substrate, is small in size, can be manufactured at low cost, and can operate at high speed. For example, it can be applied to display devices and projectors. It is being advanced.

  The mirror structure is composed of, for example, a mirror, a mirror support part that supports the mirror, and a holding part that holds the mirror support part. Here, the mirror includes a mirror main body and a light reflection layer provided on the surface of the mirror main body. The mirror support part is composed of, for example, two beams arranged on a virtual straight line, and both ends of the mirror are supported by each beam. The mirror has a structure that rotates by using the beam as a twist axis. Therefore, the mirror is not only required to be lightweight but also required to have high rigidity.

  For example, Japanese Patent Application Laid-Open Nos. 2003-172897 and 2007-310342 disclose techniques for dealing with such requests. Specifically, a rib or a reinforcing portion is provided on the back surface of the mirror main body.

JP2003-172897 JP2007-310342A

  By the way, in the techniques disclosed in these patent publications, the rib or the reinforcing portion is provided integrally with the mirror main body. In order to manufacture a mirror structure having a mirror main body provided with ribs or reinforcing portions, first, a concave portion is first formed in a silicon substrate based on a photolithography technique and an etching technique. The holding part is constituted by a thick region of the silicon substrate surrounding the recess. Next, a mirror provided with a rib or a reinforcing portion and a mirror support portion are formed on the portion of the silicon substrate exposed on the bottom surface of the concave portion based on a photolithography technique and an etching technique (for example, deep RIE method).

  Generally, the thickness of the holding part is about 0.4 mm to 0.6 mm. Moreover, the thickness of the mirror provided with the rib or the reinforcing portion is about 0.1 mm. Therefore, after forming a recess having a depth of about 0.3 mm to 0.5 mm in the silicon substrate, the silicon substrate is processed to form a mirror provided with a rib or a reinforcing portion and a mirror support portion on the bottom surface of the recess. There is a need to do. However, it is very difficult to perform such processing with high accuracy, high mass productivity, and high yield.

  Accordingly, an object of the present invention is to provide a mirror structure manufacturing method for manufacturing a mirror structure having a mirror body portion provided with a reinforcing portion with high accuracy, high mass productivity, and high yield, and An object of the present invention is to provide a mirror structure obtained by this method for manufacturing a mirror structure.

To achieve the above object, the mirror structure of the present invention comprises:
(A) Mirror main body, and a mirror provided with a light reflecting layer provided on the surface of the mirror main body,
(B) a plurality of mirror support parts for supporting the mirror, and
(C) a holding part for holding the mirror support part,
Consisting of
Each mirror support portion is composed of a meander-structure actuator having an inflection point,
Each mirror support is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects,
A reinforcing portion is provided on the back surface of the mirror main body.

In order to achieve the above object, a method for manufacturing a mirror structure of the present invention includes:
(A) Mirror main body, and a mirror provided with a light reflecting layer provided on the surface of the mirror main body,
(B) a plurality of mirror support parts for supporting the mirror, and
(C) a holding part for holding the mirror support part,
Consisting of
Each mirror support portion is composed of a meander-structure actuator having an inflection point,
Each mirror support is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects,
A method of manufacturing a mirror structure in which a reinforcing part is provided on the back surface of the mirror body part,
(A) By patterning a laminated substrate formed by laminating a bonding layer, a second active layer, an insulating layer, and a support substrate, a holding part forming region and a reinforcing part forming region are provided, and then
(B) The first active layer is bonded to the bonding layer, and then
(C) removing the support substrate and the insulating layer other than the holding portion forming region;
Comprising at least each step,
A holding unit having a structure in which a first active layer, a bonding layer, a second active layer, an insulating layer, and a support substrate are laminated;
A mirror body composed of a first active layer;
A mirror support comprising at least a first active layer, and
A reinforcing part comprising a second active layer and provided on the back surface of the mirror body part via a bonding layer;
Get.

  In the manufacturing method of the mirror structure according to the present invention, the laminated base material is patterned to provide the holding portion forming region and the reinforcing portion forming region on the laminated base material, and then the first active layer is attached to the bonding layer. Then, at least each step of removing the support substrate and the insulating layer other than the holding portion formation region is provided. Accordingly, there is no need to perform a process of forming the recess on the silicon substrate and then processing the silicon substrate for forming the mirror provided with the rib or the reinforcing portion and the mirror support portion on the bottom surface of the recess. Therefore, the mirror and the mirror support portion can be processed with high accuracy, high mass productivity, and high yield. Moreover, in the mirror structure of the present invention or the mirror structure obtained by the manufacturing method thereof, the back surface of the mirror main body portion is provided with a reinforcing portion via a bonding layer, so the weight of the mirror is reduced. High rigidity and high flatness can be imparted.

  Furthermore, in the mirror structure of the present invention or the mirror structure obtained by the method for manufacturing the same, since there are a plurality of mirror support parts for supporting the mirror, the natural frequency of the mirror support part is sufficiently high. In addition to being able to achieve high impact resistance, each mirror support is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects. The structure and the overall size can be reduced. In addition, since each mirror support portion is composed of a meander-structure actuator having an inflection point, the mirror support portion as a whole can be less bent, thereby reducing the mirror deflection. .

FIG. 1 is a schematic partial cross-sectional view of the mirror structure according to the first embodiment along arrow AA in FIG. FIG. 2 is a schematic partial cross-sectional view of the mirror structure of Example 1 along arrow BB in FIG. FIG. 3 is a schematic partial cross-sectional view of the mirror structure of Example 1 along the arrow CC in FIG. FIG. 4 is a schematic view of the mirror structure of Example 1 as viewed from above. FIG. 5 is a schematic view of the mirror structure of Example 1 as viewed from the back surface. FIGS. 6A and 6B are a schematic plan view and a schematic cross-sectional view in which a mirror support portion in the mirror structure of Example 1 is enlarged, respectively, and FIGS. FIG. 4D is a diagram schematically illustrating an arrangement state of electrodes in a mirror support portion of the mirror structure according to the first embodiment. FIGS. 7A and 7B are conceptual diagrams showing the state of displacement of the mirror support portion. FIGS. 8A and 8B are a schematic plan view and a schematic cross-sectional view, respectively, in which a mirror support portion in the mirror structure of Example 2 is enlarged. FIG. 9 is a conceptual diagram of a display device to which the mirror structure of the present invention is applied. FIG. 10 is a schematic view of the head-mounted display in Example 4 as viewed from the front. FIG. 11 is a schematic view of a head-mounted display (provided that the frame is removed) in Example 4 as viewed from the front. FIG. 12 is a schematic view of the head-mounted display in Example 4 as viewed from above. FIG. 13 is a view of a state where the head-mounted display in Example 4 is mounted on the viewer's head from above (however, only the image display device is shown and the frame is not shown). FIG. 14 is a conceptual diagram of an image display device incorporated in a head mounted display according to the fourth embodiment. FIGS. 15A and 15B are a conceptual diagram of an image display device incorporated in a head-mounted display in Example 5 and a part of a reflective volume hologram diffraction grating, respectively. It is typical sectional drawing. FIG. 16 is a schematic view of the head-mounted display in Example 6 as viewed from the front. FIG. 17 is a schematic view of the head-mounted display in Example 6 (provided that the frame is assumed to be removed) as viewed from the front. FIG. 18 is a schematic view of the head-mounted display in Example 6 as viewed from above. FIG. 19 is a schematic view of the head-mounted display in Example 7 as viewed from the front. FIG. 20 is a schematic view of the head-mounted display in Example 7 (provided that the frame is removed) as viewed from the front. FIG. 21 is a schematic view of the head-mounted display in Example 7 as viewed from above. FIG. 22 is a schematic partial cross-sectional view of a support substrate and the like for explaining the manufacturing method of the mirror structure according to the first embodiment. FIG. 23 is a schematic partial cross-sectional view of the support substrate and the like for explaining the manufacturing method of the mirror structure according to the first embodiment, following FIG. FIG. 24 is a schematic partial cross-sectional view of the support substrate and the like for explaining the manufacturing method of the mirror structure of Example 1 following FIG. FIG. 25 is a schematic partial cross-sectional view of the support substrate and the like for explaining the manufacturing method of the mirror structure of Example 1 following FIG.

Hereinafter, the present invention will be described based on examples with reference to the drawings. However, the present invention is not limited to the examples, and various numerical values and materials in the examples are examples. The description will be given in the following order.
1. 1. General description of the mirror structure of the present invention and its manufacturing method Example 1 (mirror structure of the present invention and manufacturing method thereof)
3. Example 2 (Modification of Example 1)
4). Example 3 (Display device to which the mirror structure of the present invention is applied)
5. Example 4 (head-mounted display to which the mirror structure of the present invention is applied)
6). Example 5 (Modification of Example 4)
7). Example 6 (another modification of Example 4)
8). Example 7 (another modification of Example 4), other

  In the mirror structure of the present invention or the mirror structure obtained by the manufacturing method of the mirror structure of the present invention, two opposing positions located in parallel with the rotation axis of the mirror across the rotation axis of the mirror. A plurality of mirror support portions are connected to the mirrors at each of the mirror edges or at each of two opposing mirror edges where a virtual straight line perpendicular to the rotation axis of the mirror intersects. This is preferable from the viewpoint of reducing the overall size of the mirror structure. The minimum value (N) of the number of mirror support portions connected to each of the mirror edges can be 2 and the maximum value can be 10 without limitation. The total number of mirror support parts is “2N”. Further, by increasing N, it is possible to cope with a long-axis mirror or a large mirror.

In the mirror structure of the present invention including the above preferred configuration, the back surface of the mirror main body can be provided with a reinforcing portion via a bonding layer. Such preferred embodiment or the present invention. In the manufacturing method of the mirror structure, the bonding layer can be made of SiO ₂ .

  In the mirror structure of the present invention or the mirror structure obtained by the manufacturing method of the mirror structure of the present invention including the preferred forms and configurations described above, the reinforcing portion has a portion extending in a direction orthogonal to the rotation axis of the mirror. It can be configured. Specifically, as the planar shape of the reinforcing portion, the opening is a scale pattern shape having a triangle, a square shape having a rectangular shape such as a square, a rectangle, a parallelogram, and a rhombus, and a hexagon including an equilateral hexagon. The honeycomb shape which has can be illustrated. The reinforcing portions may be provided on the back surface of the mirror main body portion evenly, that is, at a constant arrangement pitch, or unevenly, for example, depending on the distance from the rotation axis of the mirror. It may be provided.

Furthermore, in the mirror structure of the present invention including the above preferred form and configuration,
The holding part has a structure in which the first active layer, the bonding layer, the second active layer, the insulating layer, and the support substrate are laminated from the light reflecting layer side,
The mirror body part is composed of a first active layer,
The mirror support has a laminated structure of a first active layer and a piezoelectric material layer,
The reinforcing portion may be configured by the second active layer.

The mirror structure of the present invention including the preferred embodiments and configurations described above or the mirror structure obtained by the method of manufacturing the mirror structure of the present invention (hereinafter collectively referred to as “the mirror structure of the present invention”) The thickness (t _1A ) of the portion of the mirror main body located between the reinforcing portion and the reinforcing portion is the thickness of the portion of the mirror main body contacting the reinforcing portion via the bonding layer. The thickness can be made thinner than (t _1B ). Here, as a relationship between t _1A and t _1B , 0.1 ≦ t _1A / t _1B ≦ 0.5, preferably 0.2 ≦ t _1A / t _1B ≦ 0.4 can be mentioned. Further, when the thickness of the second active layer is t ₂ and the total thickness of the second active layer, the insulating layer, and the supporting substrate is t ₀ , 0.05 ≦ t ₂ / t ₀ ≦ 0.5, It is desirable to satisfy 0.1 ≦ t ₂ / t ₀ ≦ 0.3.

In the mirror structure of the present invention including the preferred embodiments described above, for example, the first active layer and the second active layer can be composed of a silicon layer, and the support substrate (also referred to as a handle layer) is a silicon substrate. The insulating layer (also called a box layer) can be made of SiO ₂ . More specifically, a so-called SOI substrate can be exemplified as a structure in which the second active layer, the insulating layer (box layer), and the support substrate (handle layer) are laminated (a part of the laminated base material). In addition, a bonding layer can be formed on the surface of a 2nd active layer by oxidizing the surface of an SOI substrate, and a laminated base material can be obtained.

  The mirror can be rotated at a high speed based on resonance, or the mirror can be rotated at a low speed based on non-resonance. It is preferable to apply to the form to be performed. However, the present invention is not limited to this. In order to rotate the mirror, for example, a drive signal such as a sine wave signal, a rectangular wave signal, or a sawtooth signal may be supplied to each mirror support portion. When the mirror is rotated at a high speed based on resonance, the frequency of the drive signal is, for example, about several kilohertz to several hundred kilohertz. When the mirror is rotated at a low speed based on non-resonance, the frequency of the drive signal is, for example, 15 Hz, 30 Hz, 60 Hz, 120 Hz, 180 Hz, 240 Hz, or the like. When the mirror is rotated based on non-resonance, the natural frequency of the mirror support portion needs to be sufficiently higher than the frequency of the drive signal. Specifically, it is preferable that the natural frequency of the mirror support portion is, for example, 4 times or more, for example, 4 to 20 times the frequency of the drive signal. Or it is preferable that the natural frequency of a mirror support part shall be 240 hertz or more, for example. In the mirror structure and the like of the present invention, since there are a plurality of mirror support portions that support the mirror, the natural frequency of the mirror support portion can be set to a sufficiently high value. The frequency of vibrations in daily life such as trains, cars, and walking is composed of frequency components of several hertz to several tens of hertz. Therefore, when the natural frequency of the mirror support part is low and close to the frequency of vibration in daily life, unnecessary resonance occurs in the mirror support part, causing a failure of the mirror structure and a decrease in life.

  In the present invention including the various preferred embodiments described above, an actuator having a meander structure is provided as described above for displacing the mirror or rotating the mirror about the rotation axis. . Here, the actuator can be composed of a bimorph type, unimorph type, monomorph type or laminated type (multimorph type) piezoelectric actuator, but is not limited to this, and other than that, an electrostatic drive actuator, a thermal drive actuator An electromagnetic drive actuator composed of a magnetostrictive material having a Joule effect whose shape changes when a magnetic field is applied, an electromagnetic drive actuator utilizing magnetic torque, or an electrochemical drive actuator composed of a polymer gel You can also.

  A unimorph type piezoelectric actuator has, for example, a structure in which a single piezoelectric material layer that expands and contracts in the length direction is formed on a base layer (support structure) constituting the actuator. The bimorph type piezoelectric actuator has a structure in which, for example, two piezoelectric material layers extending and contracting in the length direction are stacked via a base layer (support structure) constituting the actuator, and one piezoelectric material layer When is extended, the other piezoelectric material layer is contracted. There are two types of piezoelectric material layers, a type in which the polarization directions are arranged symmetrically (series type) and a type in which the polarization directions are arranged asymmetrically (in the same direction) (parallel type). A laminated piezoelectric actuator has, for example, a structure in which a large number of piezoelectric material layers that extend and contract in the length direction and a base layer are laminated. In the actuator having these structures, one end portion is driven (moved up and down) by the movement of the piezoelectric material layer that expands and contracts in the length direction, whereby the mirror is displaced, and the mirror is It rotates. The base layer (support structure) can be constituted by, for example, a silicon layer, a silicon oxide layer, or a stacked structure of a silicon layer and a silicon oxide layer. Depending on the structure of the piezoelectric actuator, the base layer can be composed of the first active layer.

As a material constituting the piezoelectric material layer, PZT [lead zirconate titanate, Pb (Zr, Ti) O ₃ ] which is a solid solution of PbZrO ₃ and PbTiO ₃ ; PZT ceramic material in which Nb, Co and Mn are added to PZT Ternary PZT ceramic material obtained by adding perovskite ABO ₃ to PZT; PbTiO ₃ ceramic material; LiNbO ₃ ceramic material; BaTiO ₃ such as BaTiO ₃ —SiO ₂ —Al ₂ O ₃ and BaTiO ₃ —Nb ₂ O ₅ Examples thereof include: ₃ series ceramic materials; magnesium-lead niobate [Pb (Mg, Nb) O ₃ ] series ceramic materials; ZnO; AlN.

The piezoelectric material layer is, for example,
(1) Various physical vapor deposition methods (PVD method) such as sputtering method including RF magnetron sputtering method and laser ablation method using excimer laser etc.
(2) MOCVD method using an organic metal compound such as Pb (C ₂ H ₅ ) ₄ , Zr (DPM) ₄ , Ti (i-C ₃ H ₇ O) ₄ as a raw material (3) For example, acetic acid Lead [Pb (CH ₃ COOH) ₂ ], titanium isopropoxide [Ti (OCH (CH ₃ ) ₂ ) ₄ ] and zircon isopropoxide [Zr (OCH ₂ CH ₂ CH ₃ ) ₄ ] as metal raw materials A sol-gel method in which a piezoelectric material layer is obtained by forming a film of the raw material solution by a spin coating method or the like and heat-treating it to obtain a piezoelectric material layer. (4) Slurry a PZT-based ceramic material powder, and spin coating method Spin coating method (5) screen printing method (6) plating method, including composite method of forming a piezoelectric material layer based on
(7) Hydrothermal synthesis method in which an aqueous solution of zirconium, titanium or the like is placed in a pressure vessel, and heated and pressurized to form a piezoelectric material layer. (8) Submicron-sized raw material powders are combined and mixed to form an aerosol. Then, it can be formed by an aerosol deposition method or the like for forming a piezoelectric material layer by spraying.

A lower electrode is provided between the base layer (support structure) constituting the actuator and the piezoelectric material layer, and an upper electrode is provided on the piezoelectric material layer. An example of the lower electrode is a Pt / Ti laminated structure. The Ti layer is in contact with the base layer, and the Ti layer functions as an adhesion layer. In addition, as a material constituting the upper electrode, platinum (Pt), gold (Au), aluminum (Al), copper (Cu), silver (Ag), ruthenium oxide (RuO _x ), iridium oxide (IrO _x ), or , Iridium oxide-hafnium (Ir-Hf-O-based material), Ru, Ru ₂ / Ru laminated structure, Ir, IrO ₂ / Ir laminated structure, Pt, Pd, Pt / Ti laminated structure, Pt / Ta Examples include a laminated structure, a laminated structure of Pt / Ti / Ta, La _0.5 Sr _0.5 CoO ₃ (LSCO), a laminated structure of Pt / LSCO, and YBa ₂ Cu ₃ O ₇ . The electrode can be formed by sputtering or pulsed laser ablation. The patterning of the electrodes can be performed by, for example, an ion milling method or an RIE method.

  When the actuator is composed of an electrostatic drive actuator, a movable electrode is provided at the end of the mirror main body, a drive electrode is provided at the holding portion facing the end of the mirror main body, and is generated between the movable electrode and the drive electrode. The mirror may be displaced, driven, and rotated by electrostatic force.

  When the actuator is composed of a thermally driven actuator, two types of material layers having different thermal expansion coefficients (for example, a laminated structure of Si layer and Au layer, a laminated structure of Si layer and Al layer, and a laminated layer of polyimide layers having different thermal expansion coefficients) A thermal bimorph type having a structure) is formed, and a temperature change is caused by, for example, passing an electric current through these two types of material layers. As a result, the actuator bends, whereby the mirror can be displaced, driven and rotated. Alternatively, when a U-shaped connection is made by connecting two beams with different thicknesses at the tip, and a current is passed, the thin beam structure has a higher resistance value than the thick beam structure, resulting in a large amount of heat generation. The mirror can be displaced, driven and rotated by bending toward the beam structure. Alternatively, the actuator may be made of a shape memory alloy made of, for example, an alloy of Ti and Ni.

  The light reflecting layer constituting the mirror can be composed of a metal film or an alloy film formed on the surface of the mirror main body (for example, various kinds of physical vapor deposition methods (PVD methods)). And various chemical vapor deposition methods (CVD methods). Specific examples of the material constituting the light reflecting layer include gold (Au), silver (Ag), and aluminum (Al). Specifically, as described above, the mirror main body can be composed of a silicon layer (first active layer). The external shape of the mirror main body is essentially an arbitrary shape such as a circle, an ellipse, an oval (a combination of a semicircle and two line segments), a square, a rectangle, a rectangle including a trapezoid, and the like. be able to. Also, the outer shape of the light reflecting layer can be essentially any shape such as a circle, an ellipse, an oval, a square, a rectangle, a rectangle including a trapezoid, and the like. The mirror main body and the light reflecting layer may have the same, similar, or similar outer shape, or may have different outer shapes. Furthermore, the mirror main body and the light reflecting layer may be the same size, or the mirror main body may be larger than the light reflecting layer.

  Specifically, the meander-structure actuator can be composed of a combination of a plurality of flat plate-like first members and a flat plate-like second member that connects ends of the first members. The other end of the first first member is connected to one end of the second first member via a short second member. Similarly, the other end of the mth first member is connected to one end of the (m + 1) th first member via a short second member. That is, it has a planar shape in which a letter “L” and a letter obtained by horizontally inverting the letter “L” are connected in the vertical direction. In addition, the horizontal bar of “L” corresponds to the first member, and the vertical bar of “L” corresponds to the second member. And the 2nd member extended from the other end of the last 1st member is connected to the mirror. On the other hand, a second member extending from one end of the first first member is connected to the holding portion. In a preferred embodiment of the present invention, a plurality of mirror support portions are connected to the mirror at each of the two opposing mirror edges positioned in parallel with the rotation axis of the mirror. One member is preferably arranged in parallel with the rotation axis of the mirror. The axial direction of the second member extending from the other end of the last first member and the axial direction of the second member extending from one end of the first first member are preferably orthogonal to the rotation axis of the mirror. The minimum value of m can be 2, and the maximum value of m is 10 without limitation.

  Each mirror support portion has an inflection point. Specifically, in such a structure, when one end of the first member extends in one first member, the other end of the first member contracts. This can be achieved by adopting a structure. More specifically, when the actuator is composed of a piezoelectric actuator, the expansion / contraction characteristics on one end side of the first member provided by the piezoelectric material layer provided on one end side of the first member, and the other end side of the first member The expansion / contraction characteristics on the other end side of the first member provided by the provided piezoelectric material layer may be reversed.

  The mirror structure of the present invention can be incorporated into or applied to, for example, a head mounted display (HMD), a projector, a radar, an endoscope, a laser printer, a barcode reader, or the like. .

  Example 1 relates to a mirror structure (MEMS scanner) of the present invention and a manufacturing method thereof. FIG. 1 shows a schematic partial cross-sectional view of the mirror structure of the first embodiment along the arrow AA in FIG. 4, and a schematic diagram of the mirror structure of the first embodiment along the arrow BB in FIG. FIG. 2 shows a typical partial cross-sectional view, and FIG. 3 shows a schematic partial cross-sectional view of the mirror structure of Example 1 along the arrow CC in FIG. FIG. 4 shows a schematic view of the mirror structure viewed from above, FIG. 5 shows a schematic view of the mirror structure of Example 1 viewed from the back side, and FIG. ), A schematic cross-sectional view taken along the arrow BB in FIG. 6A is shown in FIG. 6B, and the arrangement state of the electrodes in the mirror support portion is shown in FIG. D).

The mirror structure 10 of Example 1 is
(A) The mirror body 22 and the mirror 20 including the light reflecting layer 21 provided on the surface of the mirror body 22;
(B) A plurality of (four in the illustrated example 1) mirror support portions 50 that support the mirror 20, and
(C) a holding unit 40 that holds the mirror support unit 50;
Consists of. And
Each mirror support portion 50 is composed of a meander-structure actuator having an inflection point,
Each mirror support 50 is connected to the mirror 20 at the edge 20A, 20B of the mirror 20 where a virtual straight line orthogonal to the rotation axis AX of the mirror 20 intersects.
Specifically, a reinforcing portion 30 is provided on the back surface 25 of the mirror main body portion 22 via a bonding layer 104.

  Here, the mirror main body 22 includes a frame-shaped frame portion (frame portion) 23 and a light reflection layer forming portion 24 provided inside the frame portion 23. The mirror 20 rotates about the rotation axis AX. Further, the reinforcing portion (rib or rib structure, uneven portion) 30 has a portion extending in a direction orthogonal to the rotation axis AX of the mirror 20. Specifically, the planar shape of the reinforcing portion 30 is a cross beam shape in which the opening 31 has a square shape, and each side of the square extends in a direction parallel to the rotation axis AX and a direction orthogonal thereto.

In Example 1, the bonding layer 104 is made of SiO ₂ . The holding unit 40 has a structure in which the first active layer 105, the bonding layer 104, the second active layer 103, the insulating layer 102, and the support substrate 101 are stacked from the light reflecting layer 21 side. Further, the mirror main body 22 and the mirror support 50 are made of the first active layer 105, and the reinforcing part 30 is made of the second active layer 103. The mirror support 50 has a laminated structure of the first active layer 105 and the piezoelectric material layer 53. Here, the first active layer 105 and the second active layer 103 are made of a silicon layer, the support substrate (handle layer) 101 is made of a silicon substrate, and the insulating layer (box layer) 102 is made of SiO _2. It is configured. More specifically, the structure in which the second active layer 103, the insulating layer (box layer) 102 and the support substrate (handle layer) 101 are laminated (part of the laminated base material 100) is composed of an SOI substrate. The bonding layer 104 is formed on the surface of the second active layer 103 by oxidizing the surface of the SOI substrate. The light reflecting layer 21 constituting the mirror 20 is made of a metal film, specifically, an aluminum (Al) thin film formed on the surface of the mirror body 22. The outer shape of the mirror main body 22 is rectangular, the outer shape of the light reflecting layer 21 is also rectangular, and the mirror main body 22 is larger than the light reflecting layer 21. In the mirror main body 22 having such a rectangular outer shape, each mirror support 50 can be said to be connected to the mirror 20 at the maximum displacement portion of the mirror 20.

  A mirror support 50 is provided for displacing the mirror 20 or for rotating the mirror 20 about the torsional rotation axis AX. In the example shown in FIG. 1, the number of mirror support portions 50 is 4 (N = 2). As a whole, one end of the mirror support portion 50 is connected to the holding portion 40, and the other end is connected to the mirror 20 at the edge portions 20 </ b> A and 20 </ b> B of the mirror 20 where virtual straight lines orthogonal to the rotation axis AX of the mirror 20 intersect. ing.

  Specifically, the mirror support portion 50 formed of a meander-structure actuator has an edge portion 20A of two opposing mirrors 20 positioned parallel to the rotation axis AX of the mirror 20 with the rotation axis AX of the mirror 20 interposed therebetween. , 20B (in other words, at each of the edges 20A, 20B of two opposing mirrors 20 intersecting a virtual straight line orthogonal to the rotation axis AX of the mirror 20), a plurality of (2N = 4) mirror supports The unit 50 is connected to the mirror 20. Specifically, the meander-structure actuator includes a plurality of flat plate-like first members 51 and a first member as shown in FIGS. 6 (A), (B), (C) and (D). It is comprised from the combination of the flat plate-shaped 2nd member 52 which connects 51 edge parts. Here, the other end of the first first member 51 is connected to one end of the second first member 51 via a short second member 52. Similarly, the other end of the mth first member 51 is connected to one end of the (m + 1) th first member 51 via a short second member 52. A second member 52 extending from the other end of the last first member 51 is connected to the mirror 20. A second member 52 extending from one end of the first first member 51 is connected to the holding portion 40. Here, a plurality (N = 2) of mirror support portions 50 are connected to the mirror 20 at each of the edge portions 20A and 20B of the two opposing mirrors 20 positioned parallel to the rotation axis AX of the mirror 20. . Further, the first member 51 is arranged in parallel with the rotation axis AX of the mirror 20. On the other hand, the axial direction of the second member 52 extending from the other end of the last first member 51 and the axial direction of the second member 52 extending from one end of the first first member 51 are the rotation axis of the mirror 20. It is orthogonal to AX. In the first embodiment, m = 6, but the present invention is not limited to this.

In Example 1, the mirror support part 50 is comprised from the unimorph type piezoelectric actuator. The unimorph type piezoelectric actuator is composed of a single piezoelectric material layer 53 that expands and contracts in the length direction. The other end is driven (moved up and down) by the movement of the piezoelectric material layer 53 that expands and contracts in the length direction, thereby causing the mirror 20 to be displaced, and the mirror about the torsional rotation axis AX. 20 rotates. The piezoelectric material layer 53 is made of PZT [lead zirconate titanate, Pb (Zr, Ti) O ₃ ], which is a solid solution of PbZrO ₃ and PbTiO ₃ .

  Each mirror support 50 has an inflection point. Here, specifically, in such a structure, in one first member 51, when one end side of the first member 51 extends, the other end side of the first member 51 contracts. Can be achieved. More specifically, the expansion / contraction characteristics of one end 51 </ b> A of the first member 51 provided by the piezoelectric material layer 53 </ b> A provided on one end 51 </ b> A of the first member 51 and the other end 51 </ b> B of the first member 51 are provided. The expansion / contraction characteristics of the other end side 51B of the first member 51 provided by the piezoelectric material layer 53B are opposite characteristics. That is, a lower electrode 61 as a common electrode having a Pt layer / Ti layer laminated structure is provided on the first active layer 105 as a base layer. A piezoelectric material layer 53A is provided on the lower electrode 61 portion on one end side 51A of the first member 51, and an upper electrode 62A made of platinum (Pt) is provided on the piezoelectric material layer 53A. . On the other hand, a piezoelectric material layer 53B is provided on the lower electrode 61 portion on the other end side 51B of the first member 51, and an upper electrode 62B made of platinum (Pt) is provided on the piezoelectric material layer 53B. Yes. The lower electrode 61 is grounded, and voltages having different polarities are applied to the upper electrode 62A and the upper electrode 62B. From each of the upper electrode 62A and the upper electrode 62B, wirings 63A and 63B made of gold (Au) extend and are connected to a control circuit (not shown). 6C and 6D, the electrodes 61, 62A, 62B and the wirings 63A, 63B are hatched to clearly show them.

  The state of displacement of the mirror support 50 is shown in the conceptual diagrams of FIGS. Here, when a voltage as shown in FIG. 7A is applied to the lower electrode 61 and the upper electrodes 62A and 62B, the piezoelectric material layer 53A contracts and the piezoelectric material layer 53B expands. As a result, as shown in FIG. 7B, the first member 51 is deformed (flexed), and the entire mirror support portion 50 is also deformed (flexed). As a result, the mirror 20 can be rotated.

In order to reduce the weight of the mirror main body 22, the portion of the mirror main body 22 located between the reinforcing portion 30 and the reinforcing portion 30 is the portion of the mirror main body 22 that is in contact with the reinforcing portion 30 via the bonding layer 104. It is thinner than the thickness (t _1B ) of the part. Further, the thickness t _BL of the bonding layer 104, the height of the reinforcing portion 30 (thickness t ₂ of the second active layer 103), and the thickness of the reinforcing portion 30 (a direction parallel to and perpendicular to the rotation axis AX). T), the formation pitch P ₁ of the reinforcing portion 30 along the direction parallel to the rotation axis AX, and the formation pitch P ₂ of the reinforcement portion 30 along the direction perpendicular to the rotation axis AX are as follows. It was as follows. Furthermore, the total thickness t ₀ of the second active layer 103, the insulating layer 102, and the support substrate 101 was as follows. still,
0.05 ≦ t ₂ / t ₀ ≦ 0.5
0.1 ≦ t _1A / t _1B ≦ 0.5
Is satisfied.

[Table 1]
t _1A = 15 μm
t _1B = 45 μm
t _BL = 1μm
t ₂ = 120 μm
t = 100 μm
P ₁ = 200 μm
P ₂ = 200 μm
t ₀ = 500 μm

  Hereinafter, the manufacturing method of the mirror structure of Example 1 will be described with reference to schematic partial cross-sectional views of the support substrate and the like of FIGS. 22, 23, 24, and 25.

[Step-100]
First, the bonding layer 104 is formed on the surface of the second active layer 103 by thermally oxidizing the surface of the SOI substrate on which the second active layer 103, the insulating layer (box layer) 102, and the support substrate (handle layer) 101 are laminated. Form. As a result, a laminated base material 100 in which the bonding layer 104, the second active layer 103, the insulating layer 102, and the support substrate 101 are laminated is obtained (see FIG. 22). On the other hand, a recess 22A is formed in a part of the silicon substrate 110 (a portion that becomes a portion of the mirror main body portion 22 located between the reinforcing portion 30 and the reinforcing portion 30) based on the RIE method (see FIG. 22). This silicon substrate 110 finally becomes the first active layer 105.

[Step-110]
Next, based on the deep RIE method, the laminated base material 100 is etched from the side of the bonding layer 104, whereby the holding portion forming region 100A and the reinforcing portion forming region 100B made of the laminated base material 100 can be provided (FIG. 23).

[Step-120]
Thereafter, the first active layer 105 is bonded to the bonding layer 104. Specifically, the laminated base material 100 and the silicon substrate 110 can be laminated by superimposing and thermocompression bonding the bonding layer 104 and the surface of the silicon substrate 110 on which the recess 22A is formed. Thereafter, the silicon substrate 110 is polished and etched to thin the silicon substrate 110 and obtain the first active layer 105 (see FIG. 24).

[Step-130]
Next, the support substrate 101 and the insulating layer 102 other than the holding portion forming region 100A are removed based on a known etching technique (see FIG. 25). When the support substrate 101 is removed, the insulating layer 102 functions as an etching stop layer.

[Step-140]
Thereafter, an aluminum layer is formed on the first active layer 105 based on a well-known sputtering method. Next, by patterning the aluminum layer and the first active layer 105 based on a well-known lithography technique and dry etching technique, the mirror 20 composed of the light reflecting layer 21 and the mirror body 22 can be obtained (FIG. 1). To FIG. 5).

Through the above process,
A holding unit 40 having a structure in which a first active layer 105, a bonding layer 104, a second active layer 103, an insulating layer 102, and a support substrate 101 are laminated;
Mirror main body portion 22 and mirror support portion 50 comprising first active layer 105, and
A reinforcing portion 30 comprising a second active layer 103 and provided on the back surface 25 of the mirror main body portion 22 via a bonding layer 104;
Can be obtained.

[Step-150]
Next, a lower electrode having a stacked structure of Pt layer / Ti layer, a piezoelectric material layer, and an upper electrode made of platinum (Pt) are sequentially formed on the first active layer 105 by a well-known method. A unimorph type piezoelectric actuator can be provided by forming a film and patterning the upper electrode, the piezoelectric material layer, and the lower electrode based on a known lithography technique and dry etching technique. Furthermore, wirings 63A and 63B made of gold (Au) are formed based on a known method.

  In addition, the order of the process of the manufacturing method of the mirror structure demonstrated above can be changed suitably.

  In the manufacturing method of the mirror structure of Example 1, the laminated base material 100 is patterned to provide the holding portion forming region 100A and the reinforcing portion forming region 100B in the laminated base material 100, and then the bonding layer 104. Then, the first active layer 105 is bonded together, and then the support substrate 101 and the insulating layer 102 other than the holding portion formation region 100A are removed. Therefore, after forming the recess in the silicon substrate, it is not necessary to process the silicon substrate for forming the mirror provided with the reinforcing portion and the mirror support portion on the bottom surface of the recess. It can be processed with high accuracy, high mass productivity, and high yield. In addition, since the reinforcing portion (rib or rib structure) 30 is provided on the back surface of the mirror main body portion 22 via the bonding layer 104, the mirror 20 can be reduced in weight and rigidity.

  As is clear from Table 2, the parallel direction deflection amount and the vertical direction deflection amount in the mirror structure 10 of Example 1 are based on the parallel direction deflection amount and the vertical direction deflection amount in the mirror structures of Comparative Example 1 and Comparative Example 2. Has also decreased significantly. In general, the parallel direction deflection amount and the vertical direction deflection amount in the mirror structure are preferably (λ / 4) or less, where λ is the wavelength of incident light. From this viewpoint, the mirror structure of the first embodiment The parallel direction deflection amount and the vertical direction deflection amount in the body 10 are extremely preferable values.

In Example 1, the natural frequency f ₀ obtained by simulation when N = 2, 4, 10 is shown in Table 3 below. As the number of N increases, the natural frequency f ₀ is increased. The value of becomes higher. Table 4 below shows the results of the simulation of the relative maximum stress when a force of 1 × 10 ¹² Pa is applied to the mirror support 50 from above. When N = 2, N As compared with the case of = 10, a large stress is generated in the mirror support 50 about four times. In other words, when the number of N increases, even when a force is applied to the mirror support 50, only a smaller stress is generated. The natural frequency f ₀ in Table 3 is a value obtained by standardizing the value of N = 2 as “1.0”, and the value of “relative maximum stress” in Table 4 is a mirror when N = 10. This is a value normalized by assuming that the stress generated in the support portion 50 is “1.0”.

[Table 3]
N natural frequency f ₀
2 1.0
4 1.4
10 2.2

[Table 4]
N Relative maximum stress 2 4.0
4 2.1
10 1.0

  As described above, since a plurality of mirror support portions support the mirror, the natural frequency of the mirror support portion can be set to a sufficiently high value, and high impact resistance can be achieved. In addition, since each mirror support portion is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects, the size of the mirror structure can be reduced. In other words, if the mirror and the holding part are connected by a mirror support part made of a beam, an actuator having a meander structure is connected to the mirror support part made of a beam, and the mirror support part made of a beam is used as the rotation axis of the mirror, A minimum of two meander-structure actuators (total of at least four meander-structure actuators) are required along the rotation axis of the mirror structure, and the overall size of the mirror structure cannot be reduced. . Further, since each mirror support portion is composed of an actuator having a meander structure having an inflection point, the mirror support portion as a whole can be less bent (specifically, the second member is bent or twisted). . If the overall size of the mirror structure exceeds, for example, 20 mm to 30 mm, it becomes difficult to perform exposure in one shot with a normal stepper (semiconductor exposure apparatus), the number of necessary masks increases, and stitch alignment is performed. There is a risk that the manufacturing cost will increase due to the necessity to do so.

  The second embodiment is a modification of the first embodiment. In the second embodiment, the configurations of the lower electrode and the upper electrode in each mirror support portion 50 are different from those in the first embodiment. FIG. 8A shows a schematic plan view in which the mirror support portion in Example 2 is enlarged, and FIG. 8B shows a schematic cross-sectional view.

  In Example 2, lower electrodes 71 and 73 having a Pt layer / Ti layer laminated structure are provided on a first active layer 105 as a base layer. A piezoelectric material layer 53A is provided on the lower electrode 71 on one end side 51A of the first member 51, and an upper electrode 72 made of platinum (Pt) is provided on the piezoelectric material layer 53A. On the other hand, a piezoelectric material layer 53B is provided on the lower electrode 73 on the other end side 51B of the first member 51, and an upper electrode 74 made of platinum (Pt) is provided on the piezoelectric material layer 53B. Voltages having different polarities are applied to the lower electrode 71 and the lower electrode 73, and voltages having different polarities are also applied to the upper electrode 72 and the upper electrode 74. A wiring (not shown) made of gold (Au) extends from each electrode and is connected to a control circuit (not shown).

  Except for the above points, the mirror structure of the second embodiment and the manufacturing method thereof can be the same as the mirror structure of the first embodiment and the manufacturing method thereof.

  Example 3 relates to a display device to which the mirror structure described in Example 1 or Example 2 is applied, and more specifically to an image display device. FIG. 9 is a conceptual diagram of a display device according to the third embodiment. The display device according to the third embodiment includes, for example, a light source composed of a semiconductor laser element, collimated lens group light (shown as one lens in FIG. 9), and light emitted from the lens group. The parallel light is incident, and the parallel light is raster-scanned in the X direction and the Y direction, and emitted from the mirror structures (MEMS scanners) 10A and 10B and the mirror structure 10B described in the first or second embodiment. It is an image display device composed of a screen on which the emitted light collides and an image is finally displayed, specifically, a projector for image display. In some cases, only one of the mirror structures 10A and 10B may be configured from the mirror structure described in the first or second embodiment.

  The number of pixels in the display device may be determined based on specifications required for the image display device. As specific values of the number of pixels, 320 × 240, 640 × 480, 854 × 480, 1024 × 768, 1920 X1080 can be illustrated. The number of mirror structures is, for example, 1.

  When performing color display in a display device, the light source is emitted from a red light emitting semiconductor laser element that emits red, a green light emitting solid-state laser that emits green, a blue light emitting semiconductor laser element that emits blue, and these semiconductor laser elements. You may be comprised from the dichroic prism for putting a laser beam into one laser beam. Alternatively, the light source is composed of one semiconductor laser element that emits white light, and the white light emitted from the semiconductor laser element is sequentially passed through the red, green, and blue color filters, and red, green The three primary colors of blue light can be extracted. Alternatively, the light source can be configured to take out the three primary colors of red, green, and blue light by including one semiconductor laser element that emits white light, a dichroic prism, and a narrowband filter that performs wavelength selection. . However, the color display method is not limited to the method described above, and can be essentially any method. In addition, an organic EL (Electro Luminescence) light emitting element, an inorganic EL light emitting element, and a light emitting diode (LED) can also be used as the light source.

  When raster scanning is performed, it is preferable to rotate the mirror around the Z axis at high speed based on resonance and to rotate the mirror around the X axis at low speed based on non-resonance. In this case, the vertical scanning of the display device is performed by rotating the mirror around the X axis at a low speed, and the horizontal scanning of the display device is performed by rotating the mirror around the Z axis at a high speed. Done. In addition, since a display apparatus and the structure and structure of itself can be made into a known structure and structure, detailed description is abbreviate | omitted.

  Example 4 is also a display device to which the mirror structure described in Example 1 or Example 2 is applied, and more specifically relates to a head-mounted display (HMD).

  FIG. 10 shows a schematic view of the head-mounted display in Example 4 as viewed from the front, and FIG. 10 shows a schematic view of the head-mounted display (provided that the frame is removed) as viewed from the front. 11 shows. FIG. 12 shows a schematic view of the head-mounted display viewed from above, and FIG. 13 shows a view of the head-mounted display mounted on the head of the observer 240 from above. Furthermore, the conceptual diagram of the image display apparatus incorporated in the head mounted display in Example 4 is shown in FIG. In FIG. 13, only the image display device is shown for the sake of convenience, and the illustration of the frame is omitted.

  The number of pixels in the head-mounted display may be determined based on specifications required for the head-mounted display. As specific values of the number of pixels, 320 × 240, 640 × 480, 854 × 480, Examples are 1024 × 768 and 1920 × 1080. The number of mirror structures is, for example, 1.

The head mounted display in Example 4 is
(A) a glasses-type frame 210 attached to the head of the observer 240, and
(B) two image display devices 300,
It has.

Here, each image display device 300 includes:
(A) Light source 351,
(B) a collimating optical system 352 that collimates the light emitted from the light source 351;
(C) scanning means 353 for scanning the parallel light emitted from the collimating optical system 352, and
(D) a relay optical system 354 that relays and emits parallel light scanned by the scanning means 353;
It is composed of Note that the entire image generation apparatus 310 is housed in a housing 313 (indicated by a one-dot chain line in FIG. 14), and the housing 313 is provided with an opening (not shown). Then, light is emitted from the relay optical system 354. Each housing 313 is attached to the end portion of the coupling member 220 using screws or an adhesive (not shown). In addition, the light guide unit 320 is attached to the housing 313.

  The light source 351 includes a red light emitting element 351R that emits red light, a green light emitting element 351G that emits green light, and a blue light emitting element 351B that emits blue light. Each light emitting element includes a semiconductor laser element. The light of the three primary colors emitted from the light source 351 passes through the cross prism 355, color synthesis is performed, the optical path is unified, and enters the collimating optical system 352 having a positive optical power as a whole, It is emitted as parallel light. Then, the parallel light is reflected by the total reflection mirror 356, and is scanned by the mirror structures 10A and 10B (see also the third embodiment) of the first embodiment or the second embodiment that two-dimensionally scan the incident parallel light. Horizontal scanning and vertical scanning are performed by means 353 (only one mirror structure is shown) to form a kind of two-dimensional image and generate virtual pixels. Then, light from the virtual pixel passes through a relay optical system 354 including a known relay optical system, and a light beam that has been converted into parallel light enters the light guide unit 320.

  In the image generation device, a plurality of parallel light beams made incident on the collimating optical system 352 are incident on the light guide plate. Such a request for parallel light is made when these light beams enter the light guide plate. This light wavefront information needs to be preserved even after it is emitted from the light guide plate via the first deflecting means and the second deflecting means. In order to generate a plurality of parallel lights, specifically, for example, a light emitting portion in the cross prism 355 may be positioned at a focal length (position) in the collimating optical system 352. The collimating optical system 352 has a function of converting pixel position information into angle information in the optical system of the light guide. As the collimating optical system 352, an optical system having a positive optical power as a whole, which is a combination of a convex lens, a concave lens, a free-form surface prism, and a hologram lens, can be exemplified.

  As described above, the head-mounted display includes the coupling member 220 that couples the two image display devices 300. The coupling member 220 is on the side facing the viewer of the central portion 210C of the frame 210 located between the two pupils 241 of the viewer 240 (ie, between the viewer 240 and the frame 210), for example, a screw. (Not shown). Further, the projection image of the coupling member 220 is included in the projection image of the frame 210. That is, when the head-mounted display is viewed from the front of the observer 240, the coupling member 220 is hidden by the frame 210, and the coupling member 220 is not visually recognized.

Specifically, the distance between the attachment portion center 310A _C of one image generation device 310A and one end (one wisdom) 210A of the frame 210 is α, and the center 220 _C of the coupling member 220 is connected to one end of the frame ( The distance to 210A is β, the distance between the attachment center 310B _{C of} the other image generating device 310B and one end (one side) 210A of the frame is γ, and the length of the frame is L. When
α = 0.1 × L
β = 0.5 × L
γ = 0.9 × L
It is. In addition, 0.01 × L ≦ α ≦ 0.30 × L, preferably 0.05 × L ≦ α ≦ 0.25 × L, 0.35 × L ≦ β ≦ 0.65 × L, preferably 0.45 × L ≦ β ≦ 0.55 × L, 0.70 × L ≦ γ ≦ 0.99 × L, preferably 0.75 × L ≦ γ ≦ 0.95 × L .

  The two image display devices 300 are coupled by the coupling member 220. Specifically, the image generation devices 310A and 310B are attached to the respective end portions of the coupling member 220 so that the mounting state can be adjusted. . Each of the image generation devices 310 </ b> A and 310 </ b> B is located outside the pupil 241 of the observer 240.

  Specifically, the image generating device (specifically, the image generating devices 310A and 310B) is attached to each end of the coupling member 220, for example, through holes (see FIG. (Not shown), tapped holes (screwed portions; not shown) corresponding to the through holes are provided in the image generating devices 310A and 310B, and screws (not shown) are passed through the through holes to generate an image. Screw into holes provided in the devices 310A and 310B. A spring is inserted between the screw and the hole. Thus, the mounting state of the image generating device (the inclination of the image generating device with respect to the coupling member) can be adjusted by the tightening state of the screws. After installation, the screw is hidden by a lid (not shown). In FIGS. 11, 17, and 20, the coupling members 220 and 230 are hatched to clearly show the coupling members 220 and 230.

  The frame 210 includes a front portion 210B disposed in front of the observer 240, two temple portions 212 rotatably attached to both ends of the front portion 210B via hinges 211, and tip portions of the temple portions 212. The connecting member 220 is a central portion 210C (ordinary glasses) of the front portion 210B located between the two pupils 241 of the observer 240. (Corresponding to the bridge part). A nose pad 214 is attached to the side of the coupling member 220 facing the observer 240. In FIG. 12, FIG. 18, or FIG. 21, the nose pad 214 is not shown. The frame 210 and the coupling member 220 are made of metal, alloy, plastic, or a combination thereof, and the shape of the coupling member 220 is a curved rod shape. The shape of the coupling member 220 is essentially arbitrary as long as the projection image of the coupling member 220 is included in the projection image of the frame 210. For example, an elongated plate shape can be exemplified in addition to a rod shape. .

  Furthermore, a wiring (a signal line, a power supply line, etc.) 215 extending from one image generating apparatus 310A extends from the tip of the modern part 213 to the outside via the temple part 212 and the inside of the modern part 213. Are connected to an external circuit (control circuit) (not shown). Further, each of the image generation devices 310A and 310B includes a headphone unit 216, and a headphone unit wiring 217 extending from each of the image generation devices 310A and 310B is provided through the temple unit 212 and the modern unit 213. It extends from the front end of the modern part 213 to the headphone part 216. More specifically, the headphone section wiring 217 extends from the tip of the modern section 213 to the headphone section 216 so as to wrap around the auricle (ear shell). With such a configuration, the headphone unit 216 and the headphone unit wiring 217 are not randomly arranged, and a clean head-mounted display can be obtained.

  In addition, an image pickup device 218 composed of a solid-state image pickup device composed of a CCD or CMOS sensor and a lens (these are not shown) is attached to the central portion 210C of the front portion 210B. Specifically, a through hole is provided in the central portion 210C, and a concave portion is provided in a portion of the coupling member 220 that faces the through hole provided in the central portion 210C. 218 is arranged. The light incident from the through hole provided in the central portion 210C is condensed on the solid-state image sensor by the lens. A signal from the solid-state imaging device is sent to the image generation device 310A via a wiring (not shown) extending from the imaging device 218. Note that the wiring passes between the coupling member 220 and the front portion 210B, and is connected to one image generation device 310A. With such a configuration, it can be made difficult to visually recognize that the imaging device is incorporated in the head-mounted display.

In the fourth embodiment, as shown in FIG. 14, the light guide means 320 that is incident, guided, and emitted by the relay optical system 354 converted into parallel light includes:
(A) As a whole, it is disposed closer to the center of the face of the observer 240 than the image generating apparatus 310, the light emitted from the image generating apparatus 310 is incident, guided, and emitted toward the pupil 241 of the observer 240. Light guide plate 321,
(B) first deflecting means 330 for deflecting the light incident on the light guide plate 321 so that the light incident on the light guide plate 321 is totally reflected inside the light guide plate 321; and
(C) second deflecting means 340 for deflecting the light propagated in the light guide plate 321 by total reflection several times in order to emit the light propagated in the light guide plate 321 by total reflection from the light guide plate 321;
It is composed of The term “total reflection” means total internal reflection or total reflection inside the light guide plate. The same applies to the following.

The first deflecting unit 330 and the second deflecting unit 340 are disposed inside the light guide plate 321. The first deflecting unit 330 reflects the light incident on the light guide plate 321, and the second deflecting unit 340 transmits and reflects the light propagated through the light guide plate 321 by total reflection over a plurality of times. To do. That is, the first deflecting unit 330 functions as a reflecting mirror, and the second deflecting unit 340 functions as a semi-transmissive mirror. More specifically, the first deflecting means 330 provided inside the light guide plate 321 is made of aluminum and is composed of a light reflecting film (a kind of mirror) that reflects the light incident on the light guide plate 321. . On the other hand, the second deflecting means 340 provided inside the light guide plate 321 is composed of a multilayer laminated structure in which a large number of dielectric laminated films are laminated. The dielectric laminated film is composed of, for example, a TiO ₂ film as a high dielectric constant material and an SiO ₂ film as a low dielectric constant material. A multilayer laminated structure in which a large number of dielectric laminated films are laminated is disclosed in JP-T-2005-521099. In the drawing, a six-layer dielectric laminated film is shown, but the present invention is not limited to this. A thin piece made of the same material as that constituting the light guide plate 321 is sandwiched between the dielectric laminated film and the dielectric laminated film. In the first deflecting means 330, the parallel light incident on the light guide plate 321 is reflected (or diffracted) so that the parallel light incident on the light guide plate 321 is totally reflected inside the light guide plate 321. . On the other hand, in the second deflecting unit 340, the parallel light propagated through the light guide plate 321 by total reflection is reflected (or diffracted) a plurality of times and emitted from the light guide plate 321 in the state of parallel light.

  The first deflecting means 330 cuts a portion 324 of the light guide plate 321 where the first deflecting means 330 is provided, thereby providing the light guide plate 321 with a slope on which the first deflecting means 330 is to be formed, and vacuuming the light reflecting film on the slope. After vapor deposition, the cut out portion 324 of the light guide plate 321 may be bonded to the first deflecting unit 330. The second deflecting unit 340 is formed by laminating a large number of the same material (for example, glass) as that constituting the light guide plate 321 and a dielectric laminated film (for example, a film can be formed by a vacuum deposition method). A multilayer laminated structure is manufactured, and a portion 325 provided with the second deflecting means 340 of the light guide plate 321 is cut out to form a slope, and the multilayer laminated structure is adhered to the slope and polished to adjust the outer shape. That's fine. In this way, the light guide unit 320 in which the first deflecting unit 330 and the second deflecting unit 340 are provided inside the light guide plate 321 can be obtained.

  The first deflecting means 330 is made of a metal including an alloy as described above, for example, and reflects light incident on the light guide plate (a kind of mirror) or light incident on the light guide plate. Can be constituted by a diffraction grating (for example, a hologram diffraction grating film). Further, as described above, the second deflecting unit 340 can be composed of a multilayer laminated structure in which a large number of dielectric laminated films are laminated, a half mirror, a polarization beam splitter, and a hologram diffraction grating film.

  The light guide plate 321 has two parallel surfaces (a first surface 322 and a second surface 323) extending in parallel with the axis of the light guide plate 321. The first surface 322 and the second surface 323 are opposed to each other. Then, parallel light enters from the first surface 322 corresponding to the light incident surface, propagates through the interior by total reflection, and then exits from the first surface 322 corresponding to the light exit surface. The light guide plate 321 has two parallel surfaces (a first surface and a second surface) extending in parallel with the axis (y direction) of the light guide plate, but the surface of the light guide plate 321 on which light enters is the light guide plate. When the entrance surface and the surface of the light guide plate 321 from which light is emitted are used as the light guide plate exit surface, the light guide plate entrance surface and the light guide plate exit surface may be configured by the first surface. The surface may be configured, and the light guide plate exit surface may be configured by the second surface. As a material constituting the light guide plate 321, glass containing optical glass such as quartz glass or BK7, or plastic material (for example, PMMA, polycarbonate resin, acrylic resin, amorphous polypropylene resin, styrene resin containing AS resin) Resin). The shape of the light guide plate is not limited to a flat plate, and may have a curved shape.

  As described above, in the head-mounted display (HMD) according to the fourth embodiment, the coupling member 220 couples the two image display devices 300, and the coupling member 220 includes the two pupils of the observer 240. It is attached to the central portion 210C of the frame 210 located between 241. That is, each image display device 300 is not directly attached to the frame 210. Accordingly, when the observer 240 wears the frame 210 on the head, the temple portion 212 is expanded outward, and as a result, even if the frame 210 is deformed, the deformation of the frame 210 causes the image to be deformed. The displacement (position change) of the generation devices 310A and 310B does not occur, or even a slight amount. Therefore, it is possible to reliably prevent the convergence angle of the left and right images from changing. In addition, since it is not necessary to increase the rigidity of the front portion 210B of the frame 210, there is no increase in the weight of the frame 210, a decrease in design, and an increase in cost. Further, since the image display device 300 is not directly attached to the eyeglass-type frame 210, the design and color of the frame 210 can be freely selected according to the preference of the observer. There are few restrictions on the design, and the degree of freedom in design is high. In addition, the coupling member 220 is hidden by the frame 210 when the head-mounted display is viewed from the front of the observer. Therefore, high design and design can be given to the head-mounted display.

The fifth embodiment is a modification of the fourth embodiment. FIG. 15A shows a conceptual diagram of the image display device 400 incorporated in the head mounted display in the fifth embodiment. FIG. 15B is a schematic cross-sectional view showing an enlarged part of the reflective volume hologram diffraction grating. In the fifth embodiment, the image generating apparatus 310 has the same configuration and structure as the fourth embodiment. The light guide unit 420 has a basic configuration and structure except that the configuration and structure of the first deflection unit and the second deflection unit are different.
(A) As a whole, it is disposed closer to the center of the face of the observer 240 than the image generating apparatus 310, the light emitted from the image generating apparatus 310 is incident, guided, and emitted toward the pupil 241 of the observer 240. Light guide plate 421,
(B) first deflection means for deflecting the light incident on the light guide plate 421 so that the light incident on the light guide plate 421 is totally reflected inside the light guide plate 421;
(C) second deflecting means for deflecting the light propagated in the light guide plate 421 by total reflection multiple times in order to emit the light propagated in the light guide plate 421 by total reflection from the light guide plate 421;
This is the same as the light guide means 320 of the fourth embodiment.

  In the fifth embodiment, the first deflection unit and the second deflection unit are disposed on the surface of the light guide plate 421 (specifically, the second surface 423 of the light guide plate 421). The first deflecting unit diffracts the light incident on the light guide plate 421, and the second deflecting unit diffracts the light propagated through the light guide plate 421 by total reflection over a plurality of times. Here, the first deflecting unit and the second deflecting unit include a diffraction grating element, specifically a reflective diffraction grating element, and more specifically a reflective volume hologram diffraction grating. In the following description, the first deflecting means composed of the reflective volume hologram diffraction grating is referred to as “first diffraction grating member 430” for convenience, and the second deflecting means composed of the reflective volume hologram diffraction grating is referred to as “first This is referred to as “2 diffraction grating member 440”.

  In the fifth embodiment, the first diffraction grating member 430 and the second diffraction grating member 440 are made of different P types (specifically, P = 3, three types of red, green, and blue). In order to correspond to diffraction reflection of P types of light having a wavelength band (or wavelength), a P-layer diffraction grating layer composed of a reflective volume hologram diffraction grating is laminated. Each diffraction grating layer made of a photopolymer material is formed with interference fringes corresponding to one type of wavelength band (or wavelength), and is produced by a conventional method. More specifically, a structure in which a diffraction grating layer that diffracts and reflects red light, a diffraction grating layer that diffracts and reflects green light, and a diffraction grating layer that diffracts and reflects blue light is stacked. The diffraction grating member 430 and the second diffraction grating member 440 include. The pitch of the interference fringes formed on the diffraction grating layer (diffractive optical element) is constant, the interference fringes are linear, and are parallel to the z-axis direction. The axial direction of the first diffraction grating member 430 and the second diffraction grating member 440 is defined as the y-axis direction, and the normal direction is defined as the x-axis direction. Here, the y-axis direction of the first diffraction grating member 430 and the second diffraction grating member 440 corresponds to the X-axis direction of the mirror, and the z-axis direction of the first diffraction grating member 430 and the second diffraction grating member 440 is the mirror. This corresponds to the direction of the Y axis. 15A and 15B, the first diffraction grating member 430 and the second diffraction grating member 440 are shown as one layer. By adopting such a configuration, the diffraction efficiency increases when the light having each wavelength band (or wavelength) is diffracted and reflected by the first diffraction grating member 430 and the second diffraction grating member 440, and the diffraction acceptance angle. And the diffraction angle can be optimized.

  As described above, examples of the material constituting the first diffraction grating member 430 and the second diffraction grating member 440 include a photopolymer material. The constituent materials and the basic structure of the first diffraction grating member 430 and the second diffraction grating member 440 made of the reflective volume hologram diffraction grating may be the same as the constituent materials and structures of the conventional reflective volume hologram diffraction grating. . The reflection type volume hologram diffraction grating means a hologram diffraction grating that diffracts and reflects only + 1st order diffracted light. Interference fringes are formed on the diffraction grating member from the inside to the surface, and the method for forming the interference fringes itself may be the same as the conventional forming method. Specifically, for example, a member constituting the diffraction grating member is irradiated with object light from a first predetermined direction on one side to a member constituting the diffraction grating member (for example, photopolymer material), and at the same time Is irradiated with reference light from a second predetermined direction on the other side, and interference fringes formed by the object light and the reference light may be recorded inside the member constituting the diffraction grating member. By appropriately selecting the first predetermined direction, the second predetermined direction, the wavelength of the object light and the reference light, the desired pitch of the interference fringes on the surface of the diffraction grating member, the desired inclination angle of the interference fringes ( Slant angle) can be obtained. The inclination angle of the interference fringes means an angle formed between the surface of the diffraction grating member (or the diffraction grating layer) and the interference fringes. In the case where the first diffraction grating member 430 and the second diffraction grating member 440 are configured from a laminated structure of P-layer diffraction grating layers made of a reflective volume hologram diffraction grating, such a diffraction grating layer is laminated on the P-layer. After producing the diffraction grating layers separately, the P diffraction grating layers may be laminated (adhered) using, for example, an ultraviolet curable adhesive. In addition, after producing a single diffraction grating layer using a photopolymer material having adhesiveness, the photopolymer material having adhesiveness is sequentially attached thereon to produce a diffraction grating layer, whereby the P layer A diffraction grating layer may be produced.

  FIG. 15B is an enlarged schematic partial cross-sectional view of the reflective volume hologram diffraction grating. In the reflection type volume hologram diffraction grating, interference fringes having an inclination angle φ are formed. Here, the inclination angle φ refers to an angle formed between the surface of the reflective volume hologram diffraction grating and the interference fringes. The interference fringes are formed from the inside to the surface of the reflection type volume hologram diffraction grating. The interference fringes satisfy the Bragg condition. Here, the Bragg condition refers to a condition that satisfies the following formula (A). In equation (A), m is a positive integer, λ is the wavelength, d is the pitch of the grating plane (the interval in the normal direction of the imaginary plane including the interference fringes), and Θ is the angle of incidence of the incident on the interference fringes To do. In addition, when light enters the diffraction grating member at the incident angle ψ, the relationship among Θ, the tilt angle φ, and the incident angle ψ is as shown in Expression (B).

m · λ = 2 · d · sin (Θ) (A)
Θ = 90 °-(φ + ψ) (B)

  As described above, the first diffraction grating member 430 is disposed (adhered) to the second surface 423 of the light guide plate 421, and the parallel light incident on the light guide plate 421 from the first surface 422 is generated on the light guide plate 421. The parallel light incident on the light guide plate 421 is diffracted and reflected so as to be totally reflected inside. Furthermore, the second diffraction grating member 440 is disposed (adhered) to the second surface 423 of the light guide plate 421, and the parallel light propagated through the light guide plate 421 by total reflection is diffracted and reflected a plurality of times. Then, the light is emitted from the first surface 422 as parallel light from the light guide plate 421.

  Even in the light guide plate 421, parallel light of three colors of red, green, and blue is emitted after propagating through the interior by total reflection. At this time, since the light guide plate 421 is thin and the optical path traveling through the light guide plate 421 is long, the total number of reflections until reaching the second diffraction grating member 440 differs depending on the angle of view. More specifically, out of the parallel light incident on the light guide plate 421, the number of reflections of the parallel light incident at an angle in a direction approaching the second diffraction grating member 440 has an angle in a direction away from the second diffraction grating member 440. This is less than the number of reflections of parallel light incident on the light guide plate 421. This is parallel light that is diffracted and reflected by the first diffraction grating member 430, and parallel light incident on the light guide plate 421 with an angle in a direction approaching the second diffraction grating member 440 is opposite to this angle. This is because the angle formed with the normal line of the light guide plate 421 when the light propagating through the light guide plate 421 collides with the inner surface of the light guide plate 421 is smaller than the parallel light incident on the light guide plate 421. In addition, the shape of the interference fringes formed inside the second diffraction grating member 440 and the shape of the interference fringes formed inside the first diffraction grating member 430 are in a virtual plane perpendicular to the axis of the light guide plate 421. There is a symmetrical relationship.

  As described above, the head-mounted display in the fifth embodiment has substantially the same configuration and structure as the head-mounted display in the fourth embodiment, except that the light guide means 420 is different. Is omitted.

  The sixth embodiment is also a modification of the fourth embodiment. FIG. 16 shows a schematic view of the head-mounted display in Example 6 as viewed from the front, and the head-mounted display in Example 6 (provided that the frame is removed) is viewed from the front. A schematic diagram is shown in FIG. Moreover, the schematic diagram which looked at the head mounted display in Example 6 from upper direction is shown in FIG.

  In the sixth embodiment, the light guiding unit is arranged closer to the center side of the face of the observer 240 than the image generating apparatuses 310A and 310B, and the light emitted from the image generating apparatuses 310A and 310B is incident on the observer. It is composed of a semi-transmissive mirror 520 that emits toward 240 pupils 241. In the sixth embodiment, the light emitted from the image generating apparatuses 310A and 310B propagates through the inside of a transparent member 521 such as a glass plate or a plastic plate and enters the semi-transmissive mirror 520. However, it may have a structure that propagates in the air and enters the semi-transmissive mirror 520.

  Each of the image generation devices 310A and 310B is attached to both end portions of the coupling member 220 using, for example, screws. Further, a member 521 is attached to each of the image generation apparatuses 310A and 310B, and a semi-transmissive mirror 520 is attached to the member 521. Since the head-mounted display in the sixth embodiment has substantially the same configuration and structure as the head-mounted display in the fourth embodiment except for the above differences, detailed description is omitted.

  The seventh embodiment is also a modification of the fourth embodiment. FIG. 19 shows a schematic view of the head-mounted display in Example 4 as viewed from the front. The head-mounted display in Example 7 (provided that the frame is removed) is viewed from the front. A schematic diagram is shown in FIG. FIG. 21 shows a schematic view of the head-mounted display in Example 7 as viewed from above.

  In the head mounted display according to the seventh embodiment, unlike the fourth embodiment, the rod-shaped coupling member 230 couples the two light guides 320 instead of coupling the two image generating apparatuses 310A and 310B. ing. The two light guides 320 may be integrally manufactured, and the coupling member 230 may be attached to the integrally manufactured light guide 320.

Here, even in the head-mounted display according to the seventh embodiment, the coupling member 230 is attached to the central portion 210C of the frame 210 located between the two pupils 241 of the observer 240 using, for example, screws. Each image generation device 310 is located outside the pupil 241 of the observer 240. Each image generation device 310 is attached to an end portion of the light guide unit 320. When the distance from the center 230 _C of the coupling member 230 to one end of the frame 210 is β and the length of the frame 210 is L, β = 0.5 × L is satisfied. Also in Example 7, the values of α ′ and γ ′ are the same values as the values of α and γ of Example 4.

  In the seventh embodiment, the frame 210, each image display device 300, the image generation device 310, and the light guide means 320 are the frame 210, the image display device 300, the image generation device 310, and the light guide means described in the fourth embodiment. It has the same configuration and structure as 320. Therefore, these detailed explanations are omitted. Further, the head-mounted display in Example 7 has substantially the same configuration and structure as the head-mounted display in Example 4 except for the above differences, and thus detailed description thereof is omitted.

  Further, the configuration and structure in which the rod-shaped coupling member 230 in the seventh embodiment couples the two light guide means 320 can be applied to the head mounted display described in the fifth to sixth embodiments.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples. The mirror structure, the structure of the display device, the structure, the shape of each part, the materials used, and the manufacturing method described in the examples are examples, and can be appropriately changed. You may make the thickness of the part of the 1st active layer which comprises a mirror support part thinner than the thickness of the part of the 1st active layer which comprises a mirror main-body part. In the head-mounted display described in the fourth to seventh embodiments, in some cases, the housing may be directly attached to a frame such as a temple portion.

  In the head-mounted display described in the fourth to seventh embodiments, for example, a surface relief hologram (see US 20040062505A1) may be disposed on the light guide plate. In the light guide unit 320 of the seventh embodiment, the diffraction grating element can be formed of a transmission type diffraction grating element, or one of the first deflection unit and the second deflection unit is reflected. It is also possible to adopt a form in which the other is constituted by a transmission type diffraction grating element. Alternatively, the diffraction grating element can be a reflective blazed diffraction grating element. Further, in the embodiment, the binocular type is provided exclusively with two image display devices, but may be a single eye type provided with one image display device.

DESCRIPTION OF SYMBOLS 10 ... Mirror structure, 20 ... Mirror, 21 ... Light reflection layer, 22 ... Mirror main-body part, 22A ... Recessed part, 23 ... Frame part, 24 ... Light reflection layer Forming part, 25... Back surface of mirror main body part, 30... Reinforcing part, 31... Opening, 40 .. holding part, 50 .. mirror support part, 51. ... one end side of the first member, 51B ... the other end side of the first member, 52 ... the second member, 53, 53A, 53B ... the piezoelectric material layer, 61, 71, 73 ... Lower electrode, 62A, 62B, 72, 74 ... Upper electrode, 63A, 63B ... Wiring, 100 ... Laminated substrate, 100A ... Holding part forming area, 100B ... Reinforcing part forming area, 101 ... support substrate (handle layer), 102 ... insulating layer (box layer), 103 ... second active Layer, 104 ... bonding layer, 105 ... first active layer, 110 ... silicon substrate, 210 ... frame, 210A ... one end of the frame, 210B ... front part, 210C ..Center part of frame, 211 ... hinge, 212 ... temple part, 313 ... modern part, 214 ... nose pad, 215 ... wiring (signal line, power line, etc.), 216 ..Headphone part, 217... Headphone part wiring, 218... Imaging device, 220, 230... Coupling member, 240 .. observer, 241 .. pupil, 300, 400. Display device, 310 ... Image generation device, 313 ... Housing, 320, 420 ... Light guide means, 321, 421 ... Light guide plate, 322, 422 ... First surface of light guide plate, 323, 423 ... of the light guide plate 2 surfaces, 324, 325 ... a part of the light guide plate, 330 ... first deflection means, 340 ... second deflection means, 430 ... first deflection means (first diffraction grating member), 440 ..Second deflecting means (second diffraction grating member), 352... Collimating optical system, 353... Scanning means, 354... Relay optical system, 355. Mirror, 520, transflective mirror, 521, member, AX, rotational axis

Claims (10)

(A) Mirror main body, and a mirror provided with a light reflecting layer provided on the surface of the mirror main body,
(B) a plurality of mirror support parts for supporting the mirror, and
(C) a holding part for holding the mirror support part,
Consisting of
Each mirror support portion is composed of a meander-structure actuator having an inflection point,
Each mirror support is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects,
A mirror structure in which a reinforcing portion is provided on the back surface of the mirror main body.   2. The mirror according to claim 1, wherein a plurality of mirror support portions are connected to the mirror at each of the edges of two opposing mirrors positioned in parallel with the rotation axis of the mirror across the rotation axis of the mirror. Structure.   The mirror structure according to claim 1 or 2, wherein a reinforcing part is provided on the back surface of the mirror main body part via a bonding layer. Mirror structure according to lamination layer claim 3 made of SiO _2.   The mirror structure according to any one of claims 1 to 4, wherein the reinforcing portion has a portion extending in a direction orthogonal to the rotation axis of the mirror. The holding part has a structure in which the first active layer, the bonding layer, the second active layer, the insulating layer, and the support substrate are laminated from the light reflecting layer side,
The mirror body part is composed of a first active layer,
The mirror support has a laminated structure of a first active layer and a piezoelectric material layer,
The mirror structure according to any one of claims 1 to 5, wherein the reinforcing portion includes a second active layer. (A) Mirror main body, and a mirror provided with a light reflecting layer provided on the surface of the mirror main body,
(B) a plurality of mirror support parts for supporting the mirror, and
(C) a holding part for holding the mirror support part,
Consisting of
Each mirror support portion is composed of a meander-structure actuator having an inflection point,
Each mirror support is connected to the mirror at the edge of the mirror where a virtual straight line perpendicular to the rotation axis of the mirror intersects,
A method of manufacturing a mirror structure in which a reinforcing part is provided on the back surface of the mirror body part,
(A) By patterning a laminated substrate formed by laminating a bonding layer, a second active layer, an insulating layer, and a support substrate, a holding part forming region and a reinforcing part forming region are provided, and then
(B) The first active layer is bonded to the bonding layer, and then
(C) removing the support substrate and the insulating layer other than the holding portion forming region;
Comprising at least each step,
A holding unit having a structure in which a first active layer, a bonding layer, a second active layer, an insulating layer, and a support substrate are laminated;
A mirror body composed of a first active layer;
A mirror support comprising at least a first active layer, and
A reinforcing part comprising a second active layer and provided on the back surface of the mirror body part via a bonding layer;
Of manufacturing a mirror structure.   8. The mirror according to claim 7, wherein a plurality of mirror support portions are connected to the mirror at each of the edges of two opposing mirrors positioned in parallel with the rotation axis of the mirror across the rotation axis of the mirror. Manufacturing method of structure. Combined layer manufacturing method of the mirror structure according to claim 7 or claim 8 made of SiO ₂ bonded.   The method of manufacturing a mirror structure according to any one of claims 7 to 9, wherein the reinforcing portion has a portion extending in a direction orthogonal to the rotation axis of the mirror.

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