JP5428541B2 - Micro mirror device - Google Patents

Description

  The present invention relates to a micromirror device that reflects light in a desired direction.

  Conventionally, a micromirror device that reflects light in a desired direction using a micro electro mechanical system (MEMS) is known. The micromirror device controls the reflection direction of light by swinging a mirror included in the MEMS by an electric signal (Patent Document 1).

JP 2005-208164 A

  However, since MEMS is a device that simply vibrates in one or more directions depending on the applied voltage, voltage frequency, etc., it is necessary to grasp to some extent where the light emitted from the MEMS is on the irradiation target surface. Thus, the light cannot be accurately reflected in a desired direction.

  The present invention has been made in view of this problem, and an object thereof is to obtain a micromirror device that accurately reflects light in a desired direction.

  The micromirror device according to the present invention includes a mirror member that reflects light while swinging around a first swing axis, and protects the mirror member, and is provided in the direction of light reflection by the mirror member and reflects the mirror member. A protective member that transmits the reflected light, a reflective member that is provided on the protective member and reflects light projected from the mirror member toward the periphery of the mirror member, and a mirror that can detect the light reflected by the reflective member A light detection unit provided around the member, and a mirror control unit that controls the amplitude of the mirror member according to the light detected by the light detection unit.

  The mirror member has a flat mirror surface that reflects light, the protection member is plate-shaped, and is parallel to the mirror surface when the mirror member is not swinging, and the reflection member is provided on the mirror surface side of the protection member It is preferred that

  It is preferable that the apparatus further includes a case having a recess for storing the mirror member, and the protection member is attached to the case so as to seal the recess from the outside.

  The mirror member swings within a predetermined angle around the first swing axis, and the light reflected by the reflecting member forms a line segment around the mirror member. It is preferable that the light reflected by the member is arranged linearly with respect to the direction in which the trajectory formed around the mirror member extends.

  It is preferable that the plurality of light detection units are arranged in the vicinity of both ends of the line-shaped locus around the mirror member.

  A second mirror member that swings around a second swing axis that is orthogonal to the first swing axis is further provided, and the light reflected by the first and second mirror members is around the mirror member. A plurality of light detection units arranged on straight lines parallel to each other in a direction in which the first trajectory extends, forming a first trajectory and a second trajectory located on a straight line orthogonal to each other; A plurality of second light detectors arranged on a straight line parallel to each other in a direction in which the second locus extends, and the mirror controller according to a detection state by the light detector and the second light detector It is preferable to control the amplitude of the first and second mirror members.

  It is preferable that a plurality of light detection units are arranged in the vicinity of both end portions of the first locus and the second locus around the mirror member.

  The light detection unit is CdS, and it is preferable that the current value changes when light is received, and the mirror control unit controls the mirror member in accordance with a change in current by the light detection unit.

  The light detection part is preferably provided by sputtering.

  According to the present invention, a micromirror device that accurately reflects light in a desired direction is obtained.

It is a perspective view of a micromirror device. It is sectional drawing of the micromirror device in the II-II line | wire of FIG. It is a front view of a micromirror device. It is a perspective view of a MEMS mirror. It is sectional drawing of the micromirror device in the II-II line | wire of FIG. It is sectional drawing of the micromirror device in the II-II line | wire of FIG. It is the block diagram which showed the control apparatus of the MEMS mirror. It is the graph which showed the vibration characteristic of the MEMS mirror. It is the flowchart which showed the 1st control processing. It is the graph which showed the phase change which arises by an amplitude change. It is the flowchart which showed the 2nd control processing.

  Hereinafter, a micromirror device 10 according to an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the micromirror device 10 will be described with reference to FIGS. The micromirror device 10 mainly includes a bowl-shaped case 300 having an opening, a cover glass 200 that closes the opening of the case 300, and a MEMS mirror 100 stored in the case 300.

  A case recess is formed inside the case 300. The case recess is formed by four rectangular inner surfaces and a square case bottom surface 311, and has a square opening provided on the top surface 313 of the case 300. The case 300 includes a flange 320 that protrudes from the two outer surfaces 314 at a right angle. These two outer surfaces 314 are surfaces including opposite sides of the case bottom surface 311. The flange 320 has a surface flush with the case bottom surface 311 and has a thickness in a direction perpendicular to the case bottom surface 311.

  In the flange 320, a plurality of pin electrodes 400 are provided on a surface perpendicular to the outer surface 314 of the case 300. The pin electrode 400 penetrates the outer surface 314 of the case 300 to the case recess. The plurality of pin electrodes 400 protrude from the inner surface of the case 300 at a right angle.

  Hereinafter, the direction parallel to the top surface 313 of the case 300 and perpendicular to the projecting direction of the flange 320 is the X direction, the projecting direction of the flange 320 is the Y direction, and the direction from the case bottom surface 311 to the top surface 313 is the Z positive direction. The description will be made using right-handed coordinates with the origin O as the center of the cover glass bottom surface 202, which is the bottom surface of the cover glass 200.

  The inner side surface of the case 300 includes a first case side surface 303xn, a second case side surface 303xp, a third case side surface 303yn, and a fourth case side surface 303yp. The first case side surface 303xn and the second case side surface 303xp are orthogonal to the X axis, and the third case side surface 303yn and the fourth case side surface 303yp are orthogonal to the Y axis. The first case side surface 303xn is located on the X-axis negative direction side, and the second case side surface 303xp is located on the X-axis positive direction side. The third case side surface 303yn is located on the Y axis negative direction side, and the fourth case side surface 303yp is located on the Y axis positive direction side. A plurality of pin electrodes 400 protrude from the third case side surface 303yn and the fourth case side surface 303yp toward the inside of the case 300.

  The case bottom surface 311 is provided with the MEMS mirror 100 and a light detection member. The MEMS mirror 100 is the center of the case bottom surface 311, and mainly includes a movable part 110 and a drive electrode 160.

  The movable part 110 is mainly composed of a disk-shaped first movable part 120, an annular second movable part 130, and an annular frame part 140.

  As for the 1st movable part 120, one of two circular surfaces comprises the mirror surface 121. FIG. The second movable portion 130 is provided to surround the outer peripheral surface 122 of the first movable portion 120, and the frame portion 140 is provided to surround the outer peripheral surface 131 of the second movable portion 130. The first movable part 120, the second movable part 130, and the frame part 140 are all substantially the same thickness. The centers of the first and second movable parts 120 and 130 and the frame part 140 are concentric.

  First support portions 123 and 124 that connect the outer peripheral surface 122 of the first movable portion 120 and the inner peripheral surface 132 of the second movable portion 130 are provided. The first support parts 123 and 124 are rectangular parallelepiped plate-like members, and are provided on a plane passing through the central axis of the first movable part 120. Due to this shape and position, the first support parts 123 and 124 have elasticity in the twisting direction. Thus, the first movable portion 120 is supported so as to be swingable with respect to the second movable portion 130 with the first support portions 123 and 124 as axes. That is, the first movable part 120 can swing around the X axis.

  Second support portions 133 and 134 that connect the outer peripheral surface 131 of the second movable portion 130 and the frame portion 140 are provided. The second support parts 133 and 134 are rectangular parallelepiped plate-like members on a plane perpendicular to the plane on which the first support parts 123 and 124 are provided and passing through the central axis of the first movable part 120. Provided. Due to this shape and position, the second support parts 133 and 134 have elasticity in the twisting direction. As a result, the second movable portion 130 is supported so as to be swingable with respect to the frame portion 140 about the second support portions 133 and 134. That is, the second movable part 130 can swing around the Y axis. The swing axis of the first movable part 120 and the swing axis of the second movable part 130 are orthogonal to each other.

  The drive electrode 160 includes an X direction electrode 170 for driving the first movable part 120 around the X axis, and a Y direction electrode 180 for driving the second movable part 130 around the Y axis. The X-direction electrode 170 is composed of two substantially semicircles obtained by dividing a disk into two by diameter. In the figure, a substantially semicircle placed on the Y axis negative side of the X axis in the figure is called an X positive electrode 171, and a substantially semicircle placed on the Y axis positive side of the X axis is called an X negative electrode 172. The Y-direction electrode 180 is composed of two substantially half wheels obtained by dividing the ring shape by its diameter, and houses the X-direction electrode 170 on the inner periphery. In the figure, a substantially half wheel placed on the X axis negative side of the Y axis in the figure is called a Y negative electrode 181, and a substantially half wheel placed on the X axis positive side of the Y axis is called a Y positive electrode 182. In an idle state where no potential difference is applied to the drive electrode 160, the Z axis perpendicular to the X axis and the Y axis coincides with the normal line of the mirror surface 121 of the first movable unit 120.

  The centers of the X direction electrode 170 and the Y direction electrode 180 are placed concentrically with the centers of the first and second movable parts 120 and 130 and the frame part 140 on the Z axis. The diameter of the X direction electrode 170 is substantially equal to the diameter of the first movable part 120, and the inner diameter and outer diameter of the Y direction electrode 180 are equal to the inner diameter and outer diameter of the second movable part 130. The first and second movable parts 120 and 130 and the X and Y direction electrodes 180 are, when viewed from their central axes (that is, the Z axis), the first movable part 120 and the X direction electrode 170, and the second The movable portion 130 and the Y-direction electrode 180 are provided so as to substantially overlap with each other.

  When viewed from the central axis of the first and second movable parts 120 and 130, the X-direction electrode 170 is divided into an X positive electrode 171 and an X negative electrode 172 by the swing axis of the first movable part 120, The Y direction electrode 180 is divided into a Y negative electrode 181 and a Y positive electrode 182 by the swing axis of the second movable part 130.

  An X positive wiring 173 and an X negative wiring 174 for transferring electric charges to the X positive electrode 171 and the X negative electrode 172 are provided on the substantially semicircular tops of the X positive electrode 171 and the X negative electrode 172, respectively. A Y negative wire 183 and a Y positive wire 184 for transferring charges to the Y negative electrode 181 and the Y positive electrode 182 are respectively provided at the substantially semicircular tops of the Y negative electrode 181 and the Y positive electrode 182. The X positive wiring 173, the X negative wiring 174, the Y positive wiring 184, and the Y negative wiring 183 are connected to a power supply device (not shown), and the first and second movable parts 120 and 130 and the frame part 140 are electrically grounded. The

  The light detection member includes first to sixth X-direction light detection units PDx1 to PDx6 and first to sixth Y-direction light detection units PDy1 to PDy6.

  The first to sixth X-direction light detection units PDx1 to PDx6 are rectangular, and the longitudinal direction thereof extends in a direction parallel to the Y axis. The first to sixth X-direction light detection units PDx1 to PDx6 are arranged in order so as to be parallel to each other from the X-axis negative direction toward the positive direction. The first to third X-direction light detectors PDx1-PDx3 are provided close to the first case side surface 303xn, and the fourth to sixth X-direction light detectors PDx4-PDx6 are second case side surfaces. It is provided close to 303xp. An interval larger than the interval with other X direction detection units is provided between the third X direction light detection unit PDx3 and the fourth X direction light detection unit PDx4. The first to third X-direction light detection units PDx1-PDx3 are line-symmetric with respect to the fourth to sixth X-direction light detection units PDx4-PDx6 and a straight line passing through the center of the case bottom surface 311 and parallel to the Y axis. And a point-symmetrical relationship with respect to the center of the case bottom surface 311.

  The first to sixth Y-direction light detection units PDy1-PDy6 are also rectangular, and their longitudinal direction extends in a direction parallel to the X axis. The first to sixth Y-direction light detection units PDy1-PDy6 are arranged so as to be parallel to each other from the Y-axis negative direction toward the positive direction. The first to third Y-direction light detection units PDy1-PDy3 are provided close to the first case side surface 303yn, and the fourth to sixth Y-direction light detection units PDy4-PDy6 are provided to the second case side surface. It is provided close to 303 yp. A gap larger than the gap between the third Y-direction light detection unit PDy3 and the fourth Y-direction light detection unit PDy4 is provided between the third Y-direction light detection unit PDy4. The first to third Y-direction light detection units PDy1-PDy3 are line-symmetric with respect to the fourth to sixth Y-direction light detection units PDy4-PDy6 and a straight line passing through the center of the case bottom surface 311 and parallel to the X axis. And a point-symmetrical relationship with respect to the center of the case bottom surface 311.

  The distances from the first X-direction light detection unit PDx1, the sixth X-direction light detection unit PDx6, the first Y-direction light detection unit PDy1, and the sixth Y-direction light detection unit PDy6 to the center of the case bottom surface 311 are equal. Second X direction light detection unit PDx2, fifth X direction light detection unit PDx5, second Y direction light detection unit PDy2, fifth Y direction light detection unit PDy5, and third X direction light detection unit The same applies to the PDx3, the fourth X-direction light detection unit PDx4, the third Y-direction light detection unit PDy3, and the fourth Y-direction light detection unit PDy4.

  Between the third Y direction light detection unit PDy3 and the fourth Y direction light detection unit PDy4, and between the third Y direction light detection unit PDy3 and the fourth Y direction light detection unit PDy4, A mirror 100 is provided.

  The first to sixth X-direction light detection units PDx1 to PDx6 and the first to sixth Y-direction light detection units PDy1 to PDy6 are provided on the pin electrode 400 protruding from the third and fourth case side surfaces 303yn and 303yp, They are connected via bonding wires 401 (see FIG. 3).

  The cover glass 200 is a flat rectangular parallelepiped, and is composed of a square cover glass top surface 201 and a cover glass bottom surface 202, and four side surfaces. Cover glass 200 is attached to case 300 such that cover glass bottom surface 202 closes the opening of case 300. A light reflection film 203 is formed on the bottom surface 202 of the cover glass.

  The light reflection film 203 has a square shape and is formed on the inner side of the top surface of the case on the cover glass bottom surface 202. An area inside the light reflecting film 203 on the bottom surface 202 of the cover glass, an imaging laser transmission area 210 is formed.

  A laser light source (not shown) is provided outside the micromirror device 10 and irradiates the mirror surface 121 with laser light. The laser light passes through the cover glass 200 and reaches the mirror surface 121. The first and second movable portions 120 and 130 reflect the laser light while swinging toward an irradiation target surface (not shown) that is a two-dimensional plane. The laser light again passes through the cover glass 200 and is scanned on the irradiation target surface. By adjusting the emission timing of the laser light, it is possible to draw a desired image at a desired position on the irradiation target surface. The swing angle, period, and phase shift of the first and second movable parts 120 and 130 are controlled so that the laser beam is scanned in a desired region on the irradiation target surface. In order to control these appropriately, the light detection member detects the position of the laser beam reflected by the first and second movable parts 120 and 130.

  Of the laser light scanned by the micromirror device 10, the laser light scanned toward the outside of the imaging laser transmission region 210 on the bottom surface 202 of the cover glass is reflected toward the light detection member by the light reflection film 203 ( (See FIGS. 5 and 6). At this time, the first movable unit 120 includes the fifth Y-direction light detection unit PDy5 and the sixth Y-direction light from between the first Y-direction light detection unit PDy1 and the second Y-direction light detection unit PDy2. The second movable unit 130 is controlled so as to scan the laser beam up to the detection unit PDy6, and the second movable unit 130 is a fifth element between the first X-direction light detection unit PDx1 and the second X-direction light detection unit PDx2. The laser beam is controlled to scan between the X direction light detection unit PDx5 and the sixth X direction light detection unit PDx6. Then, according to the distance between the irradiation target surface and the micromirror device 10, the first laser light is irradiated in the imaging region provided on the irradiation target surface when the laser light is reflected in this range. To sixth X-direction light detection units PDx1-PDx6 and first to sixth Y-direction light detection units PDy1-PDy6 are determined in advance. Thereby, the user can recognize information formed in the imaging region provided on the irradiation target surface, for example, character information and image information.

  Next, the operation of the first movable part 120 will be described with reference to FIGS.

  First, a case where the first movable part 120 swings clockwise around the X axis will be described.

  A power supply device (not shown) applies an AC voltage to the X positive electrode 171 through the X positive wiring 173. When the AC voltage increases from 0 V, a voltage difference is generated between the grounded first movable part 120 and the X positive electrode 171, and the first movable part 120 and the X positive electrode 171 are generated by this voltage difference. An electrostatic force is generated between By this electrostatic force, the first movable part 120 and the X positive electrode 171 attract each other, and the first movable part 120 rotates clockwise around the X axis. When the AC voltage becomes maximum, the first movable unit 120 rotates at the maximum rotation angle.

  As the AC voltage decreases from the maximum voltage, the electrostatic force decreases, and the first movable portion 120 is parallel to the second movable portion 130 and the frame portion 140 due to the elastic force of the first support portions 123 and 124. Approaching the state. When the AC voltage becomes 0 V, the potential difference between the first movable part 120 and the X positive electrode 171 disappears and the electrostatic force disappears, and the first movable part 120 includes the second movable part 130 and the frame part 140. It becomes a parallel state.

  By repeating this, the first movable part 120 swings clockwise around the X axis.

  Next, a case where the first movable unit 120 swings counterclockwise on the X axis will be described.

  In this case, the power supply device applies an AC voltage to the X negative electrode 172 via the X negative wiring 174. When the AC voltage increases from 0 V, a voltage difference is generated between the grounded first movable part 120 and the X negative electrode 172, and the first movable part 120 and the X negative electrode 172 are generated by this voltage difference. An electrostatic force is generated between By this electrostatic force, the first movable part 120 and the X negative electrode 172 attract each other, and the first movable part 120 rotates counterclockwise on the X axis. When the AC voltage becomes maximum, the first movable unit 120 rotates at the maximum rotation angle.

  As the AC voltage decreases from the maximum voltage, the electrostatic force decreases, and the first movable portion 120 is parallel to the second movable portion 130 and the frame portion 140 due to the elastic force of the first support portions 123 and 124. Approaching the state. When the AC voltage becomes 0 V, the potential difference between the first movable part 120 and the X negative electrode 172 disappears and the electrostatic force disappears, and the first movable part 120 includes the second movable part 130 and the frame part 140. It becomes a parallel state.

  By repeating this, the first movable part 120 swings counterclockwise on the X axis.

  Next, the operation of the second movable part 130 will be described.

  First, the case where the second movable part 130 swings counterclockwise in the Y axis will be described.

  A power supply device (not shown) applies an AC voltage to the Y negative electrode 181 through the Y negative wiring 183. When the AC voltage increases from 0 V, a voltage difference is generated between the second movable part 130 and the Y negative electrode 181 that are grounded, and the second movable part 130 and the Y negative electrode 181 are generated by this voltage difference. An electrostatic force is generated between By this electrostatic force, the second movable part 130 and the Y negative electrode 181 attract each other, and the second movable part 130 rotates counterclockwise in the Y axis. When the AC voltage is maximized, the second movable unit 130 rotates at the maximum rotation angle.

  As the AC voltage decreases from the maximum voltage, the electrostatic force decreases, and the second movable part 130 is parallel to the first movable part 120 and the frame part 140 by the elastic force of the second support parts 133 and 134. Approaching the state. When the AC voltage becomes 0 V, the potential difference between the second movable part 130 and the Y negative electrode 181 disappears and the electrostatic force disappears, and the second movable part 130 includes the first movable part 120 and the frame part 140. It becomes a parallel state.

  By repeating this, the second movable portion 130 swings counterclockwise in the Y axis.

  Next, a case where the second movable unit 130 swings clockwise in the Y axis will be described.

  In this case, the power supply device applies an AC voltage to the Y positive electrode 182 via the Y positive wiring 184. When the AC voltage increases from 0 V, a voltage difference is generated between the second movable part 130 and the Y positive electrode 182 that are grounded. Due to this voltage difference, the second movable part 130 and the Y positive electrode 182 are generated. An electrostatic force is generated between By this electrostatic force, the second movable part 130 and the Y positive electrode 182 attract each other, and the second movable part 130 rotates in the Y-axis clockwise direction. When the AC voltage is maximized, the second movable unit 130 rotates at the maximum rotation angle.

  As the AC voltage decreases from the maximum voltage, the electrostatic force decreases, and the second movable part 130 is parallel to the first movable part 120 and the frame part 140 by the elastic force of the second support parts 133 and 134. Approaching the state. When the AC voltage becomes 0 V, the potential difference between the second movable part 130 and the Y positive electrode 182 disappears and the electrostatic force disappears, and the second movable part 130 includes the first movable part 120 and the frame part 140. It becomes a parallel state.

  By repeating this, the second movable part 130 swings in the Y-axis clockwise direction.

  Next, a control device 500 that controls the operation of the micromirror device 10 will be described with reference to FIG.

  The control device 500 includes a microcomputer 561, an oscillator 562, an X direction inverter 563, an X direction positive voltage amplifier 564, an X direction negative voltage amplifier 565, a counter 566, a Y direction inverter 567, a Y direction positive voltage amplifier 568, and a Y direction negative. Mainly composed of a voltage amplifier 569.

  The microcomputer 561 is connected to the light detection member, and controls the oscillator 562, the Y-direction positive voltage amplifier 568, and the Y-direction negative voltage amplifier 569 according to an analog signal received from the light detection member that has received light. A control signal is sent to the oscillator 562 to control the amplitudes in the X and Y directions.

  The microcomputer 561 records the state of the analog signal received from the light detection member.

  The oscillator 562 transmits an AC signal having a frequency corresponding to the control signal from the microcomputer 561 to the X-direction positive voltage amplifier 564, the X-direction inverter 563, and the counter 566. As the oscillator 562, a VCO (voltage controlled oscillator) or a DDS (direct digital synthesizer) is used.

  The X direction inverter 563 inverts the phase of the received AC signal and transmits the inverted AC signal to the X direction negative voltage amplifier 565. The X-direction positive voltage amplifier 564 and the X-direction negative voltage amplifier 565 amplify the AC signal to a voltage sufficient to drive the movable unit 110 and transmit the AC signal to the drive electrode 160 provided in the MEMS mirror 100.

  The movable part 110 oscillates at an oscillating frequency corresponding to the frequency of the AC signal from the X direction positive voltage amplifier 564 and the X direction negative voltage amplifier 565. When the amplitude of the AC signal is increased, the amplitude of the movable part 110 increases. When the amplitude of the AC signal is lowered, the amplitude of the movable part 110 is reduced. In this way, the laser beam reflected by the movable part 110 is scanned in the X axis positive / negative direction on the cover glass bottom surface 202.

  The counter 566 divides the frequency of the signal transmitted from the oscillator 562 by 3/4. Then, the frequency-divided signal is transmitted to the Y-direction positive voltage amplifier 568 and the Y-direction inverter 567. Similar to the X direction inverter 563, the Y direction inverter 567 transmits the inverted AC signal to the Y direction negative voltage amplifier 569. The Y-direction positive voltage amplifier 568 and the Y-direction negative voltage amplifier 569 change the voltage of the received AC signal, that is, the amplitude in accordance with the voltage control signal from the microcomputer 561, and then transmit it to the drive electrode 160 provided in the MEMS mirror 100. To do.

  The movable part 110 oscillates at an oscillation frequency corresponding to the frequency of the AC signal from the Y-direction positive voltage amplifier 568 and the Y-direction negative voltage amplifier 569 and an amplitude corresponding to the voltage. When the amplitude of the AC signal is increased, the amplitude of the movable part 110 increases. When the amplitude of the AC signal is lowered, the amplitude of the movable part 110 is reduced. In this way, the laser light reflected by the movable portion 110 is scanned in the Y axis positive / negative direction on the cover glass bottom surface 202.

  A control means for controlling the micromirror device 10 will be described with reference to FIGS. The micromirror device 10 is controlled to scan the laser beam within a predetermined range on the irradiation target surface. Hereinafter, a description will be given by replacing the scanning range of the laser light with a predetermined range of the bottom surface 202 of the cover glass corresponding to a predetermined range on the irradiation target surface.

  First, a means for scanning laser light in the X-axis direction on the cover glass bottom surface 202 will be described.

  The uppermost curve in FIG. 6 shows the time change of the laser beam irradiation position in the X-axis direction on the cover glass bottom surface 202. When the laser beam is irradiated far beyond the imaging area on the irradiation target surface, and when the laser beam is irradiated only within the imaging area, the shape of information formed in the imaging area, for example, the shape of character information or image information Collapses and the user cannot recognize the information. Therefore, the first control means is executed so that the laser beam is scanned within a range that slightly removes the imaging region. That is, the laser beam is scanned in a range that slightly removes the imaging laser transmission region 210 on the bottom surface 202 of the cover glass.

  When the laser beam outside the imaging laser transmission region 210 is reflected by the light reflection film 203 and enters the fourth X-direction light detection unit PDx4, the fourth X-direction light detection unit PDx4 sends an analog signal to the microcomputer 561. Send.

  The microcomputer 561 receives the analog signal and turns on the fourth X-direction state variable Vx4.

  Further, when the laser light is incident on the fifth and sixth X-direction light detection units PDx5 and PDx6, the fifth and sixth X-direction light detection units PDx5 and PDx6 transmit analog signals to the microcomputer 561. The microcomputer 561 receives the analog signal and turns on the fifth and sixth X-direction state variables Vx5 and Vx6.

  Next, when the laser beam returns at the maximum position in the X-axis positive direction on the bottom surface 202 of the cover glass and starts moving in the X-axis negative direction, it is reflected by the light reflecting film 203 and enters the sixth X-direction light detection unit PDx6. To do. When the sixth X-direction light detection unit PDx6 that has received the laser beam transmits an analog signal to the microcomputer 561, the microcomputer 561 receives the analog signal and turns off the sixth X-direction state variable Vx6.

  Further, when the laser light is incident on the fifth and fourth X-direction light detectors PDx5 and PDx4, the fifth and fourth X-direction light detectors PDx5 and PDx4 transmit analog signals to the microcomputer 561. The microcomputer 561 receives the analog signal and turns off the fifth and fourth X-direction state variables Vx5 and Vx4.

  The time required for the laser light to leave the imaging laser transmission region 210 and return to the imaging laser transmission region 210 again is shorter than half of the period of the movable unit 110 in the X-axis direction, that is, a half period.

  On the other hand, when the X-direction state variable in the microcomputer 561 is OFF, the laser light may move from the maximum position in the X-axis positive direction toward the imaging laser transmission region 210. At this time, each X direction light detection unit does not detect the laser light within a half cycle of the movable unit 110 after first detecting the laser light. In other words, each X-direction light detection unit does not sense the laser beam twice within a half cycle of the movable unit 110. Therefore, the microcomputer 561 changes the X-direction state variable that was turned ON when first sensed to OFF, and waits for an analog signal from the X-direction light detection unit again.

  Thereby, it is possible to determine in what range the laser light is irradiated in the X-axis direction of the cover glass 200.

  Note that the amplitude in the negative X-axis direction can be controlled by performing the same process on the first to third X-direction light detection units PDx1-PDx3. At this time, the first X-direction light detection unit PDx1 is in the sixth X-direction light detection unit PDx6, the second X-direction light detection unit PDx2 is in the fifth X-direction light detection unit PDx5, and the third X-direction is detected. The light detection unit PDx3 has a function corresponding to the fourth X-direction light detection unit PDx4.

  By performing the same process in the Y-axis direction, it is possible to determine in what range the laser light is irradiated in the Y-axis direction of the cover glass 200. At this time, the fourth, fifth, and sixth X-direction light detection units PDx4, PDx5, and PDx6 in FIG. 6 are replaced with the fourth, fifth, and sixth Y-direction light detection units PDy4, PDy5, and PDy6, respectively.

  First control processing for scanning laser light in the X-axis direction on the cover glass bottom surface 202 will be described with reference to FIGS. In the first control process, when it is determined that the amplitude of the micromirror device 10 is narrow, that is, between the fourth X-direction light detection unit PDx4 and the fifth X-direction light detection unit PDx5, the laser light is irradiated. It is executed when not.

  In step S701, the voltage of the AC signal applied to the drive electrode 160 is increased. As a result, the amplitude of the second movable part 130 increases. On the other hand, the phase of the AC signal changes due to the voltage rise of the AC signal. Thereby, the phase of the 2nd movable part 130 also changes.

  In step S702, the phase of the AC signal changed by the process in step S701 is adjusted. This adjustment is performed by adjusting the output timing of the drive pulse constituting the AC signal. Thereby, the phase of the 2nd movable part 130 is returned to the phase before the voltage of an alternating current signal is raised.

  In step S703, it is determined whether the amplitude of the second movable unit 130 is within a specified range. That is, it is determined whether or not the laser beam is irradiated between the fifth X-direction light detection unit PDx and the sixth X-direction light detection unit PDx6. When the amplitude of the second movable unit 130 is within a specified range, the process ends. If the amplitude of the second movable unit 130 is not within the specified range, the process returns to step S701, and the amplitude and phase are adjusted again.

  By this processing, laser light is irradiated from the imaging laser transmission region 210 to a position on the cover glass bottom surface 202 corresponding to the space between the fifth X-direction light detection unit PDx5 and the sixth X-direction light detection unit PDx6. The

  In addition, the same processing is performed on the first to third X-direction light detection units PDx1-PDx3 and the first to sixth Y-direction light detection units PDy1-PDy6, so that the X-axis negative direction, Y The irradiation range of the laser beam can be adjusted with respect to the positive and negative axial directions.

  A second control process for scanning laser light in the X-axis direction on the cover glass bottom surface 202 will be described with reference to FIGS. The second control process is executed when it is determined that the amplitude of the micromirror device 10 is wide, that is, when the laser beam is irradiated beyond the sixth X-direction light detection unit PDx6 in the positive X-axis direction. .

  In step S901, the voltage of the AC signal applied to the drive electrode 160 is lowered. Thereby, the amplitude of the 2nd movable part 130 becomes small. On the other hand, the phase of the AC signal changes due to the voltage rise of the AC signal. Thereby, the phase of the 2nd movable part 130 also changes.

  In step S902, the phase of the AC signal changed by the process in step S901 is adjusted. This adjustment is performed by adjusting the output timing of the drive pulse constituting the AC signal. Thereby, the phase of the 2nd movable part 130 is returned to the phase before the voltage of an alternating current signal is raised.

  In step S903, it is determined whether the amplitude of the second movable unit 130 is within a specified range. That is, it is determined whether or not the laser beam is irradiated between the fifth X-direction light detection unit PDx and the sixth X-direction light detection unit PDx6. When the amplitude of the second movable unit 130 is within a specified range, the process ends. If the amplitude of the second movable unit 130 is not within the specified range, the process returns to step S901, and the amplitude and phase are adjusted again.

  By this processing, laser light is irradiated from the imaging laser transmission region 210 to a position on the cover glass bottom surface 202 corresponding to the space between the fifth X-direction light detection unit PDx5 and the sixth X-direction light detection unit PDx6. The

  In addition, the same processing is performed on the first to third X-direction light detection units PDx1-PDx3 and the first to sixth Y-direction light detection units PDy1-PDy6, so that the X-axis negative direction, Y The irradiation range of the laser beam can be adjusted with respect to the positive and negative axial directions.

  According to this embodiment, the laser irradiation range can be accurately controlled without providing a light detection member on the laser irradiation object.

DESCRIPTION OF SYMBOLS 10 Micromirror apparatus 100 MEMS mirror 110 Movable part 120 1st movable part 121 Mirror surface 122 Outer peripheral surface 123 1st support part 130 2nd movable part 131 Outer peripheral surface 132 Inner peripheral surface 133 2nd support part 140 Frame part 160 Driving electrode 170 X direction electrode 171 X positive electrode 172 X negative electrode 173 X positive wiring 174 X negative wiring 180 Y direction electrode 181 Y negative electrode 182 Y positive electrode 183 Y negative wiring 184 Y positive wiring 200 Cover glass 201 Cover glass top surface 202 Cover glass bottom surface 203 Light reflection film 210 Imaging laser transmission region 300 Case 303xn First case side surface 303xp Second case side surface 303yn Third case side surface 303yp Fourth case side surface 311 Case bottom surface 313 Top surface 314 Outer side surface 320 Flange 400P Electrode 401 Bonding wire 500 Controller 561 Microcomputer 562 Oscillator 563 X direction inverter 564 X direction positive voltage amplifier 565 X direction negative voltage amplifier 566 Counter 567 Y direction inverter 568 Y direction positive voltage amplifier 569 Y direction negative voltage amplifier PDx1 1st X direction light detection unit PDx2 Second X direction light detection unit PDx3 Third X direction light detection unit PDx4 Fourth X direction light detection unit PDx5 Fifth X direction light detection unit PDx6 Sixth X direction light detection Unit PDy1 first Y direction light detection unit PDy2 second Y direction light detection unit PDy3 third Y direction light detection unit PDy4 fourth Y direction light detection unit PDy5 fifth Y direction light detection unit PDy6 sixth Y direction light detector

Claims (8)

A mirror member that reflects light while swinging around a first swing axis;
A protective member that protects the mirror member and transmits light reflected by the mirror member provided in the direction of light reflection by the mirror member;
Provided on a surface facing the Oite the mirror member to the protective member, a reflecting member for reflecting the light reflected from the mirror member toward the periphery of the mirror member,
A light detector provided around the mirror member so that the light reflected by the reflective member can be detected;
A mirror controller that controls the amplitude of the mirror member according to the light detected by the light detector;
A bottomed cylindrical case having an opening at the top,
The micromirror device in which the mirror member and the light detection unit are stored in a bottom portion of the case, and the opening is covered by the protective member. The mirror member has a planar mirror surface that reflects light;
The protective member is plate-shaped and is parallel to the mirror surface when the mirror member is not swinging,
The micromirror device according to claim 1, wherein the reflection member is provided on the mirror surface side of the protection member. The mirror member swings within a predetermined angle around the first swing axis;
The light reflected by the reflecting member forms a line-shaped locus around the mirror member,
The micromirror device according to claim 2, wherein the plurality of light detection units are arranged linearly with respect to a direction in which a locus formed by light reflected by the mirror member around the mirror member extends. 4. The micromirror device according to claim 3 , wherein the plurality of light detection units are arranged in the vicinity of both ends of the line-shaped locus around the mirror member. 5. The mirror member swings within a predetermined angle around a second swing axis perpendicular to the first swing axis;
The light reflected by the mirror member that swings around the first swing axis forms a first linear segment around the mirror member,
The light reflected by the mirror member that swings around the second swing axis forms a second segment that is perpendicular to the first locus around the mirror member,
The micromirror device includes a plurality of photodetectors arranged on a straight line parallel to a direction in which the first trajectory extends, and a straight line parallel to each other in a direction in which the second trajectory extends. A plurality of second light detectors,
The micromirror device according to claim 3 , wherein the mirror control unit controls the amplitude of the mirror member in accordance with a detection state by the light detection unit and the second light detection unit. The micromirror device according to claim 5 , wherein a plurality of the light detection units are arranged in the vicinity of both end portions of the first locus and the second locus around the mirror member.   2. The micromirror according to claim 1, wherein the light detection unit is CdS, and a current value changes when receiving light, and the mirror control unit controls the mirror member according to a change in current by the light detection unit. apparatus. The micromirror device according to claim 7 , wherein the light detection unit is provided by sputtering.

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