JP2010181586A - Optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase driving torque of a movable part rockably supported on an optical apparatus in which a light beam is deflected by rocking a mirror by electromagnetic driving system by increasing the outermost peripheral wiring length of a driving coil. <P>SOLUTION: The electromagnetic driving type optical apparatus is provided with driving coil installation parts separated from the movable parts. The mirrors are fixed on the upper part of the movable parts, the driving coil installation parts are disposed below the movable parts and fixed to each other by connection parts. When an electric current flows in the driving coils wired at the driving coil installation parts in a magnetic field, Lorentz force exerts on the driving coil installation parts and the movable parts and the driving coil installation parts fixed by the connection parts rock in an integrated manner. In the driving coil installation parts on which the driving coils are installed and the movable parts are provided as separate components, the outer periphery of the driving coil installation parts is made larger than that of the movable parts and the outermost peripheral wiring length of the driving coils can be made long, thus the driving torque for the movable parts can be made large. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical device that changes a reflection direction of a light beam by swinging a mirror by electromagnetic force.

  Patent Document 1 discloses an electromagnetically driven optical device 500 shown in FIG. The optical device 500 includes substrates 502 and 502, a movable portion 503, a pair of flexible beams 504 and 504 that support the movable portion 503 so as to be swingable with respect to the substrates 502 and 502, and the movable portion 503. A fixed drive coil 521, input / output terminals 523a and 523b of the drive coil 521, a drive signal generator 540 connected between the input / output terminals 523a and 523b, and a pair of magnets 550 and 550 are provided. ing. The drive coil 521 is formed in multiple windings along the outer periphery of the movable portion 503. A mirror (not shown) is installed on the upper surface of the movable portion 503.

  A magnetic field is generated in the direction indicated by the arrow B by the pair of magnets 550 and 550. When a current in the direction indicated by the arrow I is passed through the drive coil 521, a Lorentz force in the direction indicated by the arrow F is generated with respect to the drive coil 521. With this Lorentz force, a torque for swinging the movable portion 503 around the pair of flexible beams 504 and 504 is obtained. With this torque, the pair of flexible beams 504 and 504 are twisted, and the movable portion 503 swings around the pair of flexible beams 504 and 504 as swing axes.

  Further, as shown in FIG. 28, Patent Document 2 discloses an electromagnetically driven optical device 600 including a gimbal beam that can drive the movable portion 603 biaxially. The optical device 600 includes a substrate 602, a movable portion 603, a pair of first movable beams 604 and 604 extending in the x direction from the substrate 602, and each of the first movable beams 604 connected to the tip. A support beam 631 having a frame shape and a pair of second movable beams 634 and 634 extending in the y direction from the support beam 631 are provided. The movable portion 603 is supported by a pair of second movable beams 634 and 634. A mirror 605 is fixed on the upper surface of the movable portion 603. The movable portion 603 and the mirror 605 can be swung around the X axis by a pair of first movable beams 604 and 604, and can be swung around a Y axis by a pair of second movable beams 634 and 634.

  A first drive coil 621 is wired along the outer periphery of the support beam 631. A second drive coil 625 is wired along the outer periphery of the movable portion 603.

  When the first drive coil 621 is energized while the optical device 600 has a magnetic field extending in the y-axis direction, a torque for swinging the first drive coil 621 about the x-axis is obtained. When the second drive coil 625 is energized in a state where a magnetic field extending in the x-axis direction is generated in the optical device 600, a torque for swinging the second drive coil 625 about the y-axis is obtained.

  In the optical device 600, by selecting the direction of the magnetic field applied to the optical device 600 and the drive coil to be energized, the movable unit 603 can be swung around the x axis, or can be swung around the y axis. You can also.

JP 2008-76695 A JP 2003-270555 A

  There is a demand for an electromagnetically driven optical device to increase the torque for swinging the movable part. If a large torque is obtained, the driving power can be reduced. Alternatively, the swing angle of the mirror can be increased. If the outermost wiring length of the drive coil is increased, a large torque can be obtained. However, the outermost peripheral wiring length of the drive coil is limited by the outer periphery of the surface where the drive coil is wired.

  As described in Patent Document 1 and Patent Document 2, when the drive coil is installed on the movable part (in the case of Patent Document 2, the second drive coil is installed on the movable part), the drive coil The outermost peripheral wiring length is limited by the size of the movable part when the movable part is viewed from the vertical direction of the mirror. However, the size of the movable part is limited by the characteristics and applications required for the optical device. For example, in the case of realizing a mirror array that provides an image by arranging a plurality of optical devices, if the movable part is enlarged, the pixel becomes large. There are restrictions on the size of the movable part. In the conventional technique, the magnitude of the drive torque obtained is restricted by the size of the movable part that is restricted for various reasons.

  An object of the present invention is to provide a technique capable of making the outermost peripheral wiring length of the drive coil larger than the outer periphery of the movable portion.

  An optical device according to the present invention includes a substrate, a beam extending from the substrate, a movable portion supported by the beam so as to be swingable with respect to the substrate, a mirror fixed above the movable portion, and a movable portion. A connection part fixed below the drive part, a drive coil installation part fixed to the connection part and positioned below the movable part, and a drive coil fixed along the outer periphery of the drive coil installation part I have.

  When the optical device is placed in a magnetic field and the drive coil is energized, a drive torque is generated in the drive coil. As a result, the drive coil installation portion, the connection portion, the movable portion, and the mirror are integrated to deform the beam and swing relative to the substrate. The reflection direction of the light beam incident on the mirror can be changed.

  In order to place the drive coil in a magnetic field, for example, a pair of magnets may be placed in the optical device. Alternatively, an optical device may be placed between a pair of magnets. The mirror should just be fixed above the movable part, may be directly fixed to the upper surface of the movable part, and may be fixed via another member. The upper surface of the movable part may be finished to a mirror surface.

  The substrate preferably includes a flat plate and a protruding portion protruding from the flat plate. In this case, the flat plate side of the movable part is referred to as the lower side, and the opposite side is referred to as the upper side. The light beam enters the mirror from above the mirror and is reflected above the mirror.

  When the drive coil is energized in a magnetic field, Lorentz force is generated in the drive coil, and torque for swinging the drive coil installation portion is obtained. Since the drive coil installation part and the movable part are fixed by the connecting part, if the drive coil installation part swings, the movable part and the mirror also swing.

  In this invention, since the drive coil installation part is installed separately from the movable part, the outer periphery of the drive coil installation part can be made larger than the outer periphery of the movable part. The outermost peripheral wiring length of the drive coil can be increased without being restricted by the size of the movable portion.

  Here, the swinging of the movable part means that the movable part rotates about a predetermined axis with respect to the substrate by a predetermined angle, and the movable part tilts and stops and repeatedly swings. Both of them shall be included.

  In the present invention, the mirror is independently swung around two orthogonal axes (the swing angle about the Y axis can be changed without changing the swing angle about the X axis, and the swing about the Y axis can be changed). The fact that the swing angle around the X axis can be changed without changing the angle can be applied to an optical device (expressed as swinging independently around two axes). That is, the first flexible beam extending from the substrate in the first direction, the support beam connected to the first flexible beam, and extending from the support beam in the second direction (perpendicular to the first direction). In addition, the present invention can also be applied to an optical device using a gimbal-shaped beam provided with a second flexible beam connected to the movable portion.

  In the case of this type of biaxially driven optical device, the movable part tends to be small because the movable part is disposed inside the support beam. As a result, the drive coil (second drive coil in the case of Patent Document 2) is also reduced, and the drive torque (torque around the y axis in the case of Patent Document 2) tends to be reduced. According to the present invention, the driving torque is not limited by the size of the movable part. When the present invention is applied to a biaxial drive optical device in which the size of the movable portion tends to be small, a remarkable effect can be obtained.

  The optical device of the present invention can be used to construct a mirror array by integrating a plurality of optical devices. In the mirror array of the present invention, optical devices having different distances between the upper surface of the mirror and the upper surface of the drive coil installation portion are installed adjacent to each other.

  In this case, it is possible to prevent the drive coil installation portions of adjacent optical devices from being aligned on the same plane. The drive coil installation part of one adjacent optical device can be extended to a region above or below the drive coil installation part of the other adjacent optical device. By making the area of the drive coil installation part larger than the movable part, it is possible to obtain a large drive torque while preventing the aperture ratio (ratio of the mirror area per unit area of the substrate) from decreasing. According to the present invention, for example, it is possible to realize a mirror array in which the individual mirrors constituting the array can be miniaturized to make the pixels dense and the individual mirrors can be swung largely with low power.

  According to the present invention, in order to install the drive coil in the drive coil installation part installed away from the movable part, the outermost peripheral wiring length of the drive coil can be made larger than the outer periphery of the movable part.

2 is a plan view of a mirror array of Example 1. FIG. It is the II-II sectional view taken on the line of FIG. It is a perspective view of the optical apparatus which comprises the mirror array shown in FIG. It is a top view of the drive coil installation part of the optical apparatus shown in FIG. It is a figure which represents a drive coil installation surface typically. It is a figure which represents a drive coil installation surface typically. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a diagram illustrating a manufacturing process of the optical device according to Example 1. FIG. 6 is a plan view of an optical device according to Example 2. FIG. It is the XXII-XXII sectional view taken on the line of FIG. FIG. 6 is a plan view showing a drive coil installation part of Example 2. It is a top view of the mirror installation part of a modification. It is a top view of the movable part of a modification. It is XXVI-XXVI sectional view taken on the line of FIG. 24 and FIG. It is a figure which shows the optical apparatus of a prior art example. It is a figure which shows the optical apparatus of a prior art example.

Preferred embodiments according to the present invention are embodied, for example, by examples having the characteristics listed below.
(Characteristic 1) The drive coil installation portion, the connection portion, and the movable portion are substantially rigid bodies, and swing as a whole as a whole. That is, the relative displacement angle between the drive coil installation portion and the movable portion is significantly smaller than the torsion angle of the flexible beam.
(Feature 2) The substrate is composed of a plate-like lower substrate and a columnar upper substrate.
(Feature 3) A pair of magnets are arranged in the optical device.
(Feature 4) An optical device is disposed between a pair of magnets.
(Feature 5) A plurality of optical devices are arranged between a pair of magnets.
(Feature 6) A drive coil is arranged between two pairs of electromagnets. One pair of electromagnets generates a magnetic field extending around the drive coil in the X direction, and the other pair of electromagnets generates a magnetic field extending around the drive coil in the Y direction. When a magnetic field extending in the X direction is generated and the drive coil is energized, the mirror swings around the Y axis. When a magnetic field extending in the Y direction is generated and the drive coil is energized, the mirror swings around the X axis.

  FIG. 1 is a plan view of the mirror array 10 according to the first embodiment as viewed from above, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. As shown in FIGS. 1 and 2, the mirror array 10 includes an optical device 200 c, an optical device 100, and an optical device 200 d installed on the lower substrate 11. The mirror array 10 includes a pair of permanent magnets 12 and 12. The permanent magnets 12 and 12 are disposed on both sides in the X direction of the optical devices 200c, 100, and 200d. As a result, a magnetic field in the X direction as shown in FIG.

  FIG. 3 is a perspective view of the optical device 100, and FIG. 4 is a plan view of the drive coil installation unit 107 and the drive coil 121 wired to the drive coil installation unit 107. As shown in FIGS. 1 to 4, the optical device 100 is formed on the lower substrate 11, and a pair of upper substrates 102 and 102, a movable unit 103, and a movable unit 103 fixed on the lower substrate 11. Is provided with a pair of flexible beams 104, 104 that swingably support each other. The pair of flexible beams 104 and 104 connect the upper ends of the pair of upper substrates 102 and 102 and the movable portion 103, and the movable portion 103 is supported at a height away from the lower substrate 11. The movable portion 103 is supported by a pair of flexible beams 104 and 104 so as to be swingable with respect to the lower substrate 11 and the upper substrate 102. A mirror 105 is formed on the upper surface of the movable portion 103. A connecting portion 108 extends downward from the lower surface of the movable portion 103. A drive coil installation part 107 is fixed to the lower end of the connection part 108. The drive coil installation unit 107 extends substantially parallel to the movable unit 103 and has a length in the X direction longer than that of the movable unit 103. The movable part 103, the connection part 108, and the drive coil installation part 107 are substantially rigid bodies and move integrally as a whole. The pair of flexible beams 104, 104 are elongated and supple and twist relatively easily. Each part of the drive coil installation part 107, the connection part 108, and the movable part 103, and the connection point where they are connected to each other, have extremely high rigidity with respect to the flexible beam 104. The relative displacement angles of the drive coil installation portion 107, the connection portion 108, and the movable portion 103 are significantly smaller than the torsion angle of the flexible beam.

  A drive coil 121 is formed on the upper surface of the drive coil installation portion 107. As clearly shown in FIG. 4, the drive coil 121 is wound twice around the outer periphery of the drive coil installation portion 107. The drive coil 121 is fixed to the drive coil installation unit 107.

  A pair of wirings 124a and 124b penetrates the inside of the connecting portion 108 in the vertical direction. The lower end of the wiring 124 a is electrically connected to one end 121 a of the driving coil 121, and the lower end of the wiring 124 b is electrically connected to the other end 121 b of the driving coil 121. A terminal 123 a is fixed to the upper surface of one upper substrate 102, and a terminal 123 b is fixed to the upper surface of the other upper substrate 102. The terminal 123a and the wiring 124a are connected by a wiring 122a, and the terminal 123b and the wiring 124b are connected by a wiring 122b. By connecting a drive signal generator (not shown) between the input / output terminals 123a and 123b and outputting a voltage signal by the drive signal generator, for example, a current can be passed through the drive coil 121.

  In the following description, subscripts may be omitted when explaining common events. For example, since both the pair of wirings 124 a and 124 b penetrate the connection part 108, the pair of wirings 124 and 124 may be described as penetrating the connection part 108. Furthermore, it may be simplified and a pair of wirings 124 may be described as penetrating the connection portion 108.

  As shown in FIG. 3, when a current in the direction indicated by the arrow I is passed through the drive coil 121 in the magnetic field B extending in the direction perpendicular to the flexible beams 104 and 104 (X direction), Y of the drive coils 121 A Lorentz force is generated in the direction indicated by the arrow F at the portion extending in the direction. As a result, a torque for swinging the drive coil installation portion 107 around the Y axis is generated.

  Since the drive coil installation unit 107, the connection unit 108, and the movable unit 103 are substantially rigid and do not relatively displace, when the torque around the Y axis acts on the drive coil installation unit 107, the drive coil installation unit 107 and the connection unit 108, the movable portion 103, and the entire mirror 105 are united and swing around the Y axis while twisting the pair of flexible beams 104 and 104.

  As shown in FIG. 1, the width of the movable portion 103 in the Y direction (direction perpendicular to the magnetic field B) is W. As shown in FIG. 2, the length of the movable portion 103 in the X direction (direction parallel to the magnetic field B) is L. In contrast, the width in the Y direction of the drive coil installation portion 107 is W, and the length in the X direction of the drive coil installation portion 107 is 2L. Further, as shown in FIG. 2, the distance between the upper surface of the mirror 105 and the upper surface of the drive coil installation portion 107 is H1. The movable part 103 and the drive coil installation part 107 are symmetrical with respect to the connection part 108.

  In the mirror array 10, each part of the two optical devices 200c and 200d has the same configuration. In the optical devices 200c and 200d, the height of the connecting portion 208 is higher than the height of the connecting portion 108 of the optical device 100. As a result, the distance H2 between the upper surface of the mirror 205 and the upper surface of the drive coil installation unit 207 satisfies H2> H1 with respect to the distance H1 between the upper surface of the mirror 105 and the upper surface of the drive coil installation unit 107. ing. Regarding the other configurations, the configurations of the optical devices 200c and 200d and the optical device 100 are the same, and description thereof is omitted by replacing the 100th series of reference numerals attached to the same member with the 200th series. For example, the drive coil installation unit 207 has the same configuration as the drive coil installation unit 107, and the drive coil 221 is wired in the same manner as the drive coil 121. The distance from the upper surface of the lower substrate 11 to the upper surface of the mirror 105 and the distance from the upper surface of the lower substrate 11 to the mirror 205 are the same. Similar to the optical device 100, the movable unit 203 can be swung around the pair of flexible beams 204, 204 by arranging the optical device 200 in a magnetic field and passing a current through the drive coil 221.

  As shown in FIGS. 1 and 2, in the mirror array 10, the optical device 200c, the optical device 100, and the optical device 200d are arranged in this order in the X direction. The upper surface of the mirror 105 of the optical device 100 and the upper surface of the mirror 205 of the optical devices 200c and 200d are aligned at the same height.

  As shown in FIGS. 1 and 2, in this embodiment, the optical devices 100 and 200c, 200d are different in the distances H1, H2 from the upper surfaces of the movable portions 103, 203 to the upper surfaces of the drive coil installation portions 107, 207, respectively. Are adjacent to each other. The distance H1 from the upper surface of the movable portion 103 of the optical device 100 to the upper surface of the drive coil installation portion 107 and the distance H2 from the upper surface of the movable portion 203 of the optical devices 200c and 200d to the upper surface of the drive coil installation portion 207 are H2. > H1 relationship. Therefore, the drive coil installation part 107 of the optical device 100 and the drive coil installation part 207 of the optical devices 200c and 200d do not exist on the same plane. Thereby, the drive coil installation part 107 of the optical device 100 can be extended in the space between the movable part 203 and the drive coil installation part 207 of the optical devices 200c and 200d. Further, the drive coil installation portion 207 of the optical devices 200 c and 200 d can be extended to a space between the drive coil installation portion 107 of the optical device 100 and the lower substrate 11. Therefore, as shown in FIGS. 1 and 2, the drive coil installation portions 107 and 207 having a larger area than the movable portions 103 and 203 can be arranged without providing a large gap between the movable portions 103 and 203. it can. Small mirrors can be arranged without gaps while using a large drive coil.

  As shown in FIG. 1 and FIG. 2, by passing a current through the drive coils 121, 221, and 221 in a magnetic field B extending in a direction (X direction) perpendicular to the longitudinal direction of the flexible beams 104, 204, 204, the optical The movable parts 103, 203, 203 of the devices 100, 200c, 200d can be swung. As a means for generating a magnetic field, as described above, a permanent magnet may be used to always generate a magnetic field. Or you may make it generate a magnetic field as needed using an electromagnet. In addition, a magnetic field generator may be installed for each optical device constituting the mirror array 10. In this case, a magnet may be incorporated in the optical device. Or you may arrange | position an optical apparatus between a pair of magnets. Alternatively, one magnetic field generating means for generating a magnetic field common to a plurality of optical devices constituting the mirror array 10 may be shared by the plurality of optical devices.

  Next, how the drive torque changes when the area of the surface where the drive coil is wired is increased will be described. FIG. 5 shows a case where the drive coil is wired only once along the outer periphery of the surface having a length of 2 L and a width of W. FIG. 6 shows a case where the drive coil is wired along the outer periphery of the surface having the length L and the width W. As shown in FIGS. 5 and 6, the swing shaft of the movable portion is located above the center portion in the length direction of the surface on which the drive coil is wired. FIG. 5 schematically shows a case where the drive coil is wired only once around the drive coil installation portion 107 of the present embodiment, and FIG. 6 shows a case where the drive coil is wired only once around the movable portion 103 of the present embodiment. The case where it does is represented typically.

  When drive coils of the same material and the same cross-sectional area are wired along the outer periphery of the surface shown in FIGS. 5 and 6, the drive coil has a wiring length substantially the same as the outer peripheral length of the surface to be wired. When the wiring length of the drive coil is approximated to be equal to the outer peripheral length of the surface to be wired, the length of the drive coil is 4L + 2W in the case of FIG. 5 and 2L + 2W in the case of FIG. Based on this, the drive torque Ta when the drive coil is installed on the surface shown in FIG. 5 is compared with the drive torque Tb when the drive coil is installed on the surface shown in FIG.

A drive torque T _a in the case of FIG. 5, the driving torque T _b in the case of Figure 6 can be respectively represented by the following formula. Here, _Ia is _a current flowing through the drive coil shown in FIG. 5, and _Ib is a current flowing through the drive coil shown in FIG. The drive torque T does not depend on the distance between the movable part and the drive coil installation part.

If the specific resistance of the drive coil is ρ, the wiring length is l, and the cross-sectional area perpendicular to the direction of current flow is s, the resistance R of the drive coil can be obtained by R = ρ (l / s). Therefore, when the drive voltage of the drive coil shown in FIG. 5 is V _a and the drive voltage of the drive coil shown in FIG. 6 is V _b , the drive voltages V _a and V _b are expressed by the following formulas according to Ohm's law. be able to.

When the currents I _a and I _b are obtained from the equations (3) and (4) and used in the equations (1) and (2), the drive torques T _a and T obtained when the drive voltage is V _a = V _b = V Each _b is as shown in the following equations (5) and (6), and the torque ratio T _b / T _a can be obtained by the equation (7).

As shown in Expression (7), the drive torque can be increased by making the length of one side of the surface where the drive coil is wired twice that of the movable portion. For example, in the above formula (7), if L = W, T _a / T _b = 4/3, and the driving torque can be increased by 30% or more when the same driving voltage is applied. Further, when the same drive voltage is applied (V _a = V _b = V), W _a which is the heat generation amount in the drive coil shown in FIG. 5 and W _b which is the heat generation amount in the drive coil shown in FIG. Is obtained as follows.

As shown in Expression (10), the amount of heat generated can be reduced by making the length of one side of the surface where the drive coil is wired twice that of the movable portion. For example, in the above formula (10), if L = W, the heat generation amount ratio is W _a / W _b = 2/3, and when the same drive voltage is applied, the heat generation amount is reduced by 30% or more. Can do.

  As described above, according to the optical device of the present embodiment, since the drive coil installation part is installed separately from the movable part, the outermost peripheral wiring length of the drive coil can be made larger than the outer periphery of the movable part. As a result, the torque for swinging the movable part can be increased and the amount of heat generated by the drive coil can be reduced.

  In this embodiment, a plurality of optical devices having the outermost wiring length of the drive coil larger than that of the movable part are integrated and used as a mirror array. In the mirror array of this embodiment, optical devices having different distances between the upper surface of the mirror and the upper surface of the drive coil installation portion are adjacent to each other, and the adjacent drive coil installation portions are not located on the same plane. Thereby, even if a drive coil having a larger area than the movable part is used, adjacent movable parts can be arranged close to each other. The mirror area (aperture ratio) per unit area of the substrate does not become too small. For example, when a projector is configured using the mirror array according to this embodiment, it is possible to simultaneously increase the number of pixels, reduce power consumption, and ensure a certain level of brightness.

  Next, a method for manufacturing the mirror array 10 will be described with reference to FIGS. In addition, about the other structure of the mirror array 10, the manufacturing method of the optical apparatus using the general MEMS technique used conventionally can be applied.

  First, as the material substrate 301, for example, a substrate made of single crystal silicon is prepared. Next, thermal oxidation or the like is performed to form an insulating layer 302 made of an oxide film on the surface of the material substrate 301. Next, a first sacrificial layer 303 is formed on the surface of the insulating layer 302 using, for example, polycrystalline silicon, and further thermal oxidation is performed to form an insulating layer 304 on the surface of the first sacrificial layer 303. Thereby, the laminated body shown in FIG. 7 can be obtained.

  Next, after the polycrystalline silicon layer 305 is formed on the surface of the insulating layer 304, photoetching (which means a series of processes from photolithography to etching) is performed to pattern the polycrystalline silicon layer 305. The polycrystalline silicon layer 305 is patterned according to the shape and size of the drive coil installation portions 207 and 207 of the optical devices 200c and 200d. Next, an insulating layer 306 is formed on the surface of the polycrystalline silicon layer 305 by thermal oxidation or the like. Next, the first metal layer 307 is formed using a metal such as Pt, Cu, or Au. Further, the first metal layer 307 is patterned into the shape and size of the drive coils 221 and 221 by photoetching. Thereby, the laminated body shown in FIG. 8 can be obtained.

  Next, photo-etching is performed on the insulating layers 304 and 306 to partially expose the first sacrificial layer 303 as shown in FIG. The insulating layers 304 and 306 are removed leaving the periphery of the polycrystalline silicon layer 305, and the polycrystalline silicon layer 305 surrounded by the insulating layers 304 and 306 is connected to the drive coil installation portions 207 and 207 of the optical devices 200c and 200d. Become. A second sacrificial layer 309 is further formed of polycrystalline silicon on the surface of the stacked body in the state of FIG. 9, and the surface of the second sacrificial layer 309 is planarized by CMP (Chemical Mechanical Polishing) or the like. Thereafter, thermal oxidation or the like is performed to form an insulating layer 310 made of an oxide film on the surface of the second sacrificial layer 309. Thereby, the laminated body shown in FIG. 10 can be obtained.

  Next, a polycrystalline silicon layer 311 is formed on the surface of the insulating layer 310, photoetching is performed, and the polycrystalline silicon layer 311 is patterned. The polycrystalline silicon layer 311 is patterned according to the shape and size of the drive coil installation portion 107 of the optical device 100. Next, an insulating layer 312 is formed on the surface of the polycrystalline silicon layer 311 by thermal oxidation or the like. Further, the second metal layer 313 is formed using a metal such as Pt, Cu, Au, etc., and the second metal layer 313 is patterned into the shape and size of the drive coil 121 by photoetching. Thereby, the laminated body shown in FIG. 11 can be obtained.

  Next, photoetching is performed on the insulating layers 310 and 312 to partially expose the second sacrificial layer 309 as shown in FIG. The insulating layers 310 and 312 are removed leaving the periphery of the polycrystalline silicon layer 311, and the polycrystalline silicon layer 311 surrounded by the insulating layers 310 and 312 serves as the drive coil installation portion 107 of the optical device 100. A third sacrificial layer 314 is further formed of polycrystalline silicon on the surface of the stacked body in the state of FIG. 12, and the surface of the third sacrificial layer 314 is planarized by CMP (Chemical Mechanical Polishing) or the like. Thereby, the laminated body shown in FIG. 13 can be obtained.

  Next, photoetching is performed on the second sacrificial layer 309 and the third sacrificial layer 314 to remove portions that become the connection portions 108 of the optical device 100 and the connection portions 208 and 208 of the optical devices 200c and 200d. Further, an insulating layer 315 is formed on the surfaces of the second sacrificial layer 309 and the third sacrificial layer 314 by thermal oxidation or the like. Thereby, the laminated body shown in FIG. 14 can be obtained. As shown in FIG. 14, a part of the insulating layers 306 and 312 and a part of the first metal layer 307 and the second metal layer 313 provided on the upper surface thereof are exposed.

  A polycrystalline silicon layer 316 is formed on the surface of the stacked body in the state shown in FIG. 14, and the polycrystalline silicon layer 316 is planarized by CMP. In this step, the insulating layer 315 formed on the surface of the third sacrificial layer 314 is also removed by CMP. Further, an insulating layer 317 is formed on the surface of the stacked body by thermal oxidation or the like. Thereby, the laminated body shown in FIG. 15 can be obtained. As shown in FIG. 15, the insulating layer 315 formed on the side surfaces of the portions that become the connection portions 108, 208, and 208 remains.

  Next, portions to be the wirings 124a, 124b, 224a, 224b, 224a, and 224b are formed in part of the portions to be the connection portions 108, 208, and 208. A part of the polycrystalline silicon layer 316 and the insulating layer 317 is removed by photoetching, and a hole reaching the first metal layer 307 and the second metal layer 313 is formed. The holes are provided in portions where the wirings 124a, 124b, 224a, 224b, 224a, 224b are formed. Further, a third metal layer 318 is formed from a metal such as Pt, Cu, or Au in the formed hole. Thereby, the laminated body shown in FIG. 16 can be obtained.

  A polycrystalline silicon layer 319 is formed on the surface of the stacked body shown in FIG. 16, and further, photoetching is performed to pattern the polycrystalline silicon layer 319. The polycrystalline silicon layer 319 is patterned according to the shape and size of the movable parts 103, 203, 203 of the optical devices 100, 200c, 200d. Thereafter, when the surface of the laminate is covered with the insulating layer 320 by thermal oxidation or the like, the laminate shown in FIG. 17 can be obtained.

Next, photoetching is performed on the insulating layers 317 and 320 to partially expose the third sacrificial layer 314 as shown in FIG. The polycrystalline silicon layer 319 surrounded by the insulating layers 317 and 320 becomes a part of the movable parts 103, 203, and 203 of the optical devices 100, 200c, and 200d. Further, as shown in FIG. 18, holes are provided in the insulating layers 317 and 320 and the polycrystalline silicon layer 319, and the third metal layer 318 is exposed on the upper surface side of the stacked body. Next, a fourth metal layer 321 is formed on the surface of the laminate shown in FIG. 18 with a metal such as Al or Au. Photoetching is performed on the fourth metal layer 321, and the shapes of the mirrors 105, 205, 205, the input / output terminals 123a, 123b, 223a, 223b, 223a, 223b, and the wirings 122a, 122b, 222a, 222b, 222a, 222b are formed. The fourth metal layer 321 is patterned according to the size. Thereby, the laminated body in the state shown in FIG. 19 can be obtained. The first sacrificial layer 303, the second sacrificial layer 309, and the third sacrificial layer 314 are removed by performing vapor phase isotropic etching with XeF ₂ gas on the stacked body in the state of FIG. Thereby, as shown in FIG. 20, the mirror array 10 can be manufactured.

  According to said manufacturing method, the mirror array 10 which concerns on a present Example can be manufactured by applying a general MEMS manufacturing technique. Since it is not necessary to significantly change the conventional manufacturing process, it is possible to manufacture the mirror array 10 without greatly increasing the labor, cost, and time in the manufacturing process.

  21 is a plan view of the optical device 400 according to the present embodiment, and FIG. 22 is a cross-sectional view taken along line XXII-XXII in FIG. As shown in FIGS. 21 and 22, the optical device 400 includes a lower substrate 41, a pair of upper substrates 402 and 402, a movable portion 403, and a beam 432 that supports the movable portion 403 so as to be swingable. The beam 432 has a frame shape supported by the pair of first flexible beams 404 and 404 extending in the X direction from the upper ends of the pair of upper substrates 402 and 402 and the pair of first flexible beams 404 and 404. And a pair of second flexible beams 434 and 434 extending from the frame-shaped support beam 431 to the inside of the support beam 431 in the Y direction. The movable portion 403 is supported by the pair of second flexible beams 434 and 434. The beam 432 has a gimbal shape, and the movable portion 403 can swing around the X axis with respect to the lower substrate 41 (the first flexible beam 404 is twisted), or can swing around the Y axis. Yes (second flexible beam 434 twists).

  A mirror 405 is formed on the upper surface of the movable portion 403. A drive coil installation unit 407 is installed on the lower surface side of the movable unit 403, and the lower surface of the movable unit 403 and the upper surface of the drive coil installation unit 407 are connected by a rigid connection unit 408.

  FIG. 23 is a plan view of the drive coil installation portion 407. As shown in FIGS. 21 to 23, the drive coil 421 is installed on the upper surface of the drive coil installation unit 407. Input / output terminals 423a and 423b of the drive coil 421 are installed on the upper surfaces of the upper substrates 402 and 402, and are connected to the wirings 424a and 424b penetrating the connection portion 408 by the wirings 422a and 422b, respectively. The lower end of the wiring 424a is electrically connected to one end 421a of the driving coil 421a, and the lower end of the wiring 424b is electrically connected to one end 421b of the driving coil 421b. The drive coil 421 is wound twice along the outer periphery of the drive coil installation portion 407. As in the first embodiment, a drive signal generator (not shown) is connected between the input / output terminals 423a and 423b, and a current can be passed through the drive coil 421 by outputting a voltage signal, for example. As shown in FIG. 21 and the like, the outer periphery of the movable portion 403 is substantially equal to the outer periphery of the square with one side L1, and the outer periphery of the drive coil installation portion 407 is substantially equal to the outer periphery of the square with one side L2. As apparent from FIG. 22, the outermost peripheral wiring length of the drive coil 421 is larger than the outer peripheral length of the outer shape of the movable portion 403.

In this embodiment, in FIG. 23 to the drive coil 421 flows in the direction of current indicated by the arrow I, when making a magnetic field in the direction indicated by the arrow B1 around the drive coil 421, the Lorentz force shown by the arrow F ₁ in the driving coil 421 As a result, the movable portion 403 can be swung around the pair of second flexible beams 434 and 434 as swing axes. Further, when making the magnetic field in the direction indicated by the arrow B2 around the drive coil 421, the Lorentz force shown in the drive coil 421 as an arrow _{F 2} acts, the first flexible beam 404, 404 of the movable portion 403 a pair It can be swung as a swing shaft. By applying a current to the drive coil 421 and controlling the strength and direction of the magnetic fields B1 and B2, the drive torque T ₂ of the movable part 403 when the second flexible beams 434 and 434 are used as the swing shafts, the first possible it is possible to control the drive torque _{T 1} of the movable portion 403 in the case where the Shiwahari 404, 404 and the pivot shaft. In this embodiment, it is preferable to use means capable of controlling the strength and direction of the magnetic field, such as an electromagnet, as means for generating the magnetic field.

  As in the first embodiment, since the entire rigidity of the drive coil installation part 407, the connection part 408, and the movable part 403 is high and swings integrally, when the Lorentz force acts on the drive coil installation part 407, The movable part 403 and the drive coil installation part 407 swing together. The connecting portion 408 has such a rigidity that it does not bend when Lorentz force acts on the drive coil installation portion 407.

  The beam 432 according to the present embodiment includes first flexible beams 404 and 404 extending in the X direction and second flexible beams 434 and 434 extending in the Y direction, and the movable portion 403 is orthogonal to each other. It can swing independently about the swing shaft in two directions. Also in this type of biaxial oscillating optical device, the outer periphery of the drive coil 421 can be made larger than the outer periphery of the movable portion 403 by separately installing the drive coil installing portion 407 and the movable portion 403. Since the outer periphery of the drive coil 421 can be increased, the drive torque for swinging the movable portion 403 can be increased. In addition, the amount of heat generated in the drive coil 421 can be reduced.

  Further, according to the present embodiment, in the optical device that swings around the two orthogonal swing axes, the same is true whether it swings around the X axis or the Y axis. Current is passed through the drive coil. By controlling the strength of the magnetic field, it can be swung around the X axis or swung around the Y axis. If the strength of the magnetic field B1 extending in the X direction is the same as the strength of the magnetic field B2 extending in the Y direction, the magnitude of the driving torque around the X axis and the Y axis around without changing the magnitude of the current flowing through the driving coil. The magnitude of the drive torque can be made equal.

  In this embodiment, the same current is supplied to the same drive coil, and the direction and strength of the drive torque of the movable part are controlled by controlling the strength and direction of the magnetic field. Alternatively, the swinging direction can be changed by changing the direction of the magnetic field while keeping the magnitude of the magnetic field constant. In this case, the torque around the X-axis and the Y-axis can be changed by changing the amount of current applied to the drive coil in the state where the magnetic field in the X direction is applied and the amount of current supplied to the drive coil in the state where the magnetic field in the Y direction is applied. The surrounding torque can be changed. Alternatively, two series of drive coils may be wired in the drive coil installation part. A first drive coil for swinging the movable part around the X axis and a second drive coil for swinging around the Y axis may be provided separately. If it does in this way, it is possible to control the drive torque of a movable part also by controlling the direction and magnitude | size of the electric current of a 1st drive coil and a 2nd drive coil.

  In the first and second embodiments described above, the mirror is directly installed on the upper surface of the movable portion, but is supported so as to be swingable by the mirror installation surface on which the mirror is installed and the beam. The movable part may be installed separately. For example, as illustrated in FIGS. 24 to 26, a mirror installation unit 435 is installed on the upper surface of the movable unit 403 of the optical device 400 so as to be separated from the movable unit 403, and the movable unit 403 and the mirror installation unit 435 are rigid mirrors. It may be fixed by the connecting portion 448. If the movable part 403 and the mirror installation part 435 are fixed by a rigid mirror connection part 448, and the movable part 403 and the drive coil installation part 407 are fixed by a rigid connection part 408, the drive coil installation part 407 is movable. The unit 403 and the mirror installation unit 435 swing together. As shown in FIGS. 24 to 26, the area of the mirror 405 can be made larger than the area of the movable part 403, and the aperture ratio can be further increased.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

10 Mirror array 11, 41 Lower substrate 100, 200c, 200d, 400 Optical device 102, 202, 402 Upper substrate 103, 203, 403 Movable portion 104, 204 Flexible beam 105, 205, 405 Mirror 107, 207, 407 Drive coil Installation portion 108, 208, 408 Connection portion 121, 221, 421 Driving coil 121a, 121b, 421a, 421b End portion 123a, 123b, 223a, 223b, 423a, 423b Input / output terminals 124a, 124b, 224a, 224b, 424a, 424b Wiring 301 Material substrate 302, 304, 306, 310, 312, 315, 317, 320 Insulating layer 303 First sacrificial layer 305, 311, 316, 319 Polycrystalline silicon layer 306 Insulating layer 307 First metal layer 309 Second sacrificial layer 313 Second Gold Layer 314 third sacrificial layer 318 a third metal layer 321 fourth metal layer 404 first flexible beam 431 supporting beam 432 beam 434 second flexible beams 435 mirror installation portion 448 mirror connection section

Claims (3)

A substrate,
A beam extending from the substrate;
A movable part supported by the beam so as to be swingable with respect to the substrate;
A mirror fixed above the movable part;
A connecting portion fixed below the movable portion;
A drive coil installation section fixed to the connection section and positioned below the movable section;
Comprising a drive coil fixed along the outer periphery of the drive coil installation portion;
When the drive coil is energized in a magnetic field, the drive coil installation portion, the connection portion, the movable portion, and the mirror deform the beam and swing with respect to the substrate. The beam is
A first flexible beam extending in a first direction from the substrate;
A support beam connected to the first flexible beam;
The optical apparatus according to claim 1, further comprising: a second flexible beam extending from the support beam in a second direction orthogonal to the first direction and connected to the movable portion. . A mirror array in which a plurality of the optical devices according to claim 1 or 2 are integrated,
The mirror array, wherein the plurality of optical devices are installed such that optical devices having different distances between the upper surface of the mirror and the upper surface of the drive coil installation portion are adjacent to each other.

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