JP2007058107A - Micromirror element and movable structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rock a mirror part without providing a pre-offset displacement between comb-shaped electrodes. <P>SOLUTION: The offset displacement is formed between the interdigital electrodes 5 on the side mirror part 2 and on the side of frame part 3 by applying an electric voltage on a piezoelectric element 6 when the mirror part 2 is rocked with the interdigital electrodes 5. Thus, mirror part 2 is rocked without providing the pre-offset displacement between interdigital electrodes 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a micromirror element that switches an optical path of a light beam suitable for application to the field of optical communication and optical measurement equipment, and a movable structure suitable for application to a micromirror element and a motion sensor.

A conventional micromirror element includes a mirror part that reflects incident light in a desired angular direction on a mirror surface, a frame part that is formed on the outer peripheral part of the mirror part and is formed of a substantially rectangular frame, and the mirror part is a frame part. The mirror unit is configured to be engaged with a connecting part that is suspended and supported, and a side wall part of the mirror part and a side wall part of the frame that faces the side wall part, and uses an electrostatic force generated by applying a voltage. (See Patent Documents 1 and 2). And according to such a structure, it becomes possible to rock | fluctuate a mirror part with low electric power.
JP 2004-13099 A (see FIG. 1) Japanese Patent Laid-Open No. 9-101474 (see FIG. 1)

  However, in the conventional micromirror element, it is necessary to form an offset displacement between the comb-shaped electrode on the mirror side and the comb-shaped electrode on the frame side during the initial operation, but the offset displacement is formed between the comb-shaped electrodes. Therefore, it is very difficult to form the offset displacement because the semiconductor process is difficult.

  The present invention has been proposed in view of the above-described circumstances, and an object of the present invention is to provide a micromirror element and a movable structure capable of swinging a mirror portion (movable portion) without providing an offset displacement in advance between comb electrodes. Is to provide.

  In the micromirror element and the movable structure according to the present invention, when the mirror part (movable part) is swung by the comb-tooth electrode, an offset displacement is formed between the comb-tooth electrodes on the mirror part (movable part) side and the frame part side. A piezoelectric element is provided at the connecting portion.

  According to the micromirror element and the movable structure according to the present invention, when the mirror part (movable part) is swung by the comb-teeth electrode, a voltage is applied to the piezoelectric element so that the mirror part (movable part) side and the frame part side are applied. Since the offset displacement can be formed between the comb-tooth electrodes, the mirror portion (movable portion) can be swung without providing the offset displacement between the comb-tooth electrodes in advance.

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

  As shown in FIG. 1, a micromirror element 1 according to an embodiment of the present invention includes a mirror unit 2 that switches a light path of a light beam by reflecting the light beam at a desired angle on a mirror surface, and an outer periphery of the mirror unit 2. A frame part 3 formed on the frame part, a bending spring part 4 for moving and holding the mirror part 2 relative to the frame part 3, a side wall part of the mirror part 2 and a side wall part of the frame part 3 facing the side wall part And a comb-tooth electrode 5 that swings the mirror portion 2 using an electrostatic force generated by applying a voltage, and a piezoelectric element 6 is provided on the surface of the bending spring portion 4. It has been.

  The piezoelectric element 6 is deformed from the state shown in FIG. 2 (a) to the state shown in FIG. 2 (b) in response to a voltage applied to the piezoelectric element electrode 7, and the mirror part 2 side and the frame part are deformed. An offset displacement is formed between the three comb electrodes 5. According to such a configuration, by forming an offset displacement of 0.5 ° between the comb-tooth electrodes 5 during the initial operation, a displacement amount of about 15 ° can be formed between the comb-tooth electrodes 5 during resonance. . 2 is a view of the flexure spring portion 4 as viewed from the direction A shown in FIG.

  In this embodiment, when the mirror unit 2 is swung, a voltage is applied to the comb-teeth electrode 5 on the frame unit 3 side via the power supply electrodes 8a and 8b. Further, the mirror part 2 is connected to the GND electrode 9 via the bending spring part 4 and is kept at the ground potential. Further, an insulating portion 9 is formed between the feeding electrodes 8a and 8b and the GND electrode 9 of the frame portion 3 so that the voltage applied to the feeding electrodes 8a and 8b is not applied to the mirror portion 2 via the bending spring portion 4. It is configured.

  In this embodiment, the mirror surface of the mirror unit 2 is coated with a metal corresponding to the wavelength of the light beam to be used. In the present embodiment, the mirror unit 2 is used for switching the optical path of the light beam. However, the mirror unit 2 can be used as a motion sensor by detecting a change in the capacitance of the mirror unit 2. .

  As is clear from the above description, in the micromirror element 1 according to the embodiment of the present invention, the piezoelectric element 6 is provided on the surface of the bending spring part 4, and the mirror part 2 (movable comb) is formed using the comb-teeth electrode 5. When swinging, as an initial operation (time T = −T1 to 0), a voltage is applied to the piezoelectric element 6 via the piezoelectric element electrode 7 as shown in FIGS. 3 (a) and 4 (a). As a result, the bending spring portion 4 is deformed, and an offset displacement is formed between the comb electrode 5 on the mirror portion 2 side and the frame portion 3 side.

  Then, after forming the offset displacement, the voltage application to the piezoelectric element 6 is stopped, and the electrode to which the voltage is applied is switched between the power supply electrode 8a and the power supply electrode 8b. Switching between the left comb-tooth electrode (fixed comb (L)) and the right comb-tooth electrode (fixed comb (R)), the mirror unit 2 is swung (FIGS. 3B, 3C and 4). (See (b) and (c)).

  That is, according to the micromirror element 1 according to the embodiment of the present invention, when the mirror part 2 is swung by the comb electrode 5, a voltage is applied to the piezoelectric element 6 so that the mirror part 2 side and the frame part 3 side are applied. Since the offset displacement is formed between the comb-teeth electrodes 5, the mirror part 2 can be swung without providing the offset displacement between the comb-teeth electrodes 5 in advance. As a result, since the micromirror element can be manufactured without using a complicated semiconductor process, the productivity and yield of the micromirror element can be improved.

  In the above embodiment, as shown in FIG. 5, a substrate 11 facing the mirror unit 2 may be provided, and an electrode 12 may be provided on the surface of the substrate 11 facing the mirror unit 2. According to such a configuration, a voltage is applied to the electrode 11 to generate an electrostatic force, thereby assisting the swing of the mirror unit 2 during the initial operation or increasing the size of the swing of the mirror unit 2. Can be. In addition, as shown in FIG. 6, an additional frame portion 13 may be provided on the outer peripheral portion of the frame portion 3, and the frame portion 3 and the additional frame portion 13 may be connected by a spring portion 14. According to such a configuration, the mirror unit 2 can be swung in the biaxial direction.

  As mentioned above, although embodiment which applied the invention made by the present inventors was described, this invention is not limited by the description and drawing which make a part of indication of this invention by this embodiment. That is, it should be added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the scope of the present invention.

It is a schematic diagram which shows the structure of the micromirror element used as embodiment of this invention. It is sectional drawing of the bending spring part and piezoelectric element seen from the A direction shown in FIG. It is a schematic diagram for demonstrating operation | movement of the micromirror element shown in FIG. It is a timing chart figure of voltage application at the time of rocking a mirror part. It is a schematic diagram which shows the structure of the application example of the micromirror element shown in FIG. It is a schematic diagram which shows the structure of the application example of the micromirror element shown in FIG.

Explanation of symbols

1: Micromirror element 2: Mirror part 3: Frame part 4: Deflection spring part 5: Comb electrode 6: Feed electrode 7: GND electrode 8: Insulating part 9: Guide part 11: Substrate 12: Electrode 13: Additional frame part 14: Spring part

Claims (4)

A mirror unit that switches the optical path of the light beam by reflecting the light beam;
A frame part formed on the outer periphery of the mirror part;
A connecting part that moves and holds the mirror part relative to the frame part;
A comb-shaped electrode that is provided so as to mesh with a side wall portion of the mirror portion and a side wall portion of the frame portion facing the side wall portion, and swings the mirror portion using an electrostatic force generated by applying a voltage. And
The connecting portion is provided with a piezoelectric element that forms an offset displacement between the mirror portion side and the frame portion side comb electrode when the mirror portion is swung by the comb tooth electrode. Mirror element. The micromirror device according to claim 1,
A micromirror element comprising a substrate facing the mirror portion, and an electrode for applying a voltage to the comb-tooth electrode is provided on a surface of the substrate facing the mirror portion. The micromirror device according to claim 1 or 2,
A micromirror element comprising an additional frame portion formed on an outer peripheral portion of the frame portion, wherein the frame portion and the additional frame portion are connected by a spring portion. A swingable movable part;
A frame portion formed on an outer peripheral portion of the movable portion;
A connecting portion that moves and holds the movable portion relative to the frame portion;
A comb-shaped electrode that is provided so as to mesh with a side wall portion of the movable portion and a side wall portion of the frame portion facing the side wall portion, and swings the movable portion using an electrostatic force generated when a voltage is applied. And
The movable portion characterized in that the connecting portion is provided with a piezoelectric element that forms an offset displacement between the comb-shaped electrodes on the movable portion side and the frame portion side when the movable portion is swung by the comb-shaped electrodes. Construction.

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