JP2005148495A - Electrostatic actuator, optical switch and optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic actuator, an optical switch and an optical device which are compact and highly integrated. <P>SOLUTION: The electrostatic actuator 18 has a beam-shaped member 6, a fixed electrode 8 and a voltage source 11 which applies an electric voltage between the beam-shaped member 6 and the fixed electrode 8. Electrostatic force is generated between the beam-shaped member 6 and the fixed electrode 8 by applying the electric voltage with the voltage source 11. Further, a plurality of electrode parts 7 which are arranged in a comb shape are provided on the beam-shaped member 6 and a plurality of electrode parts 9 arranged in a comb shape and inserted between respective electrode parts 7 are provided on the fixed electrode 8. Protruded parts 7a and 9a are provided on the electrode parts 7 and 9. The protruded parts maybe provided at least at the electrode parts 7 of the beam-shaped member (movable electrode) 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrostatic actuator, an optical switch, and an optical device used in optical communication and the like.

As a technique belonging to such a field, for example, an optical switch described in Non-Patent Document 1 below is known. This optical switch has an electrostatic actuator provided with a mirror, and further has two sets of movable and fixed electrodes facing each other. The movable electrode is provided in the electrostatic actuator, and is attracted to the fixed electrode by an electrostatic force generated between the movable electrode and the fixed electrode. The electrostatic actuator moves with the movement of the movable electrode. Each set of movable electrodes is moved in the opposite direction, and by appropriately moving one of the movable electrodes, the electrostatic actuator is moved in a desired direction, and on the optical path of the optical switch. The mirror is moved to a position where the passing light is blocked or passed.
SPIE Conference on Micromachined Devices and Components SPIE Vol.3876 1999

  However, in the above prior art, two pairs of a movable electrode and a fixed electrode are required to move the electrostatic actuator. Therefore, since the space is taken as much, the optical switch becomes large and high integration becomes difficult.

  An object of the present invention is to provide an electrostatic actuator, an optical switch, and an optical device that are small and highly integrated.

  The electrostatic actuator of the present invention has a movable electrode, a fixed electrode, and a means for generating an electrostatic force between the movable electrode and the fixed electrode, and the movable electrode includes a plurality of comb teeth. The first electrode portion is provided, and the fixed electrode is provided with a plurality of second electrode portions arranged in a comb shape and inserted between the first electrode portions, and the first electrode portion has a bulge portion. Is provided.

  In such an electrostatic actuator, for example, when an electrostatic force is generated between the movable electrode and the fixed electrode in a state where the movable electrode and the fixed electrode are separated from each other, the first electrode portion and the second electrode portion attract each other. As a result, the movable electrode is attracted to the fixed electrode. In the present specification, the state where the movable electrode and the fixed electrode are separated from each other means a state where the second electrode portion is not inserted between the first electrode portions. On the other hand, the second electrode portion is inserted between the first electrode portions. For example, the distal end portion of the second electrode portion is located closer to the proximal end side of the first electrode portion than the bulging portion provided in the first electrode portion. When an electrostatic force is generated between the movable electrode and the fixed electrode, the movable electrode is pulled away from the fixed electrode by the second electrode portion and the bulging portion of the first electrode portion attracting each other. Therefore, since the movable electrode can be pulled and separated from the fixed electrode with one fixed electrode, it can be made compact and highly integrated. In addition, the bulging part may be provided in both the 1st electrode part and the 2nd electrode part, and the effect similar to the case where it is provided only in the 1st electrode part can be acquired also in this case.

  It is preferable that the bulging portion is provided at the tip portion of the first electrode portion. Thereby, since the 1st electrode part can be shortened, size reduction can be achieved further.

  Further, it is preferable to have a stopping means for stopping the movable electrode that moves so as to be attracted to the fixed electrode at a position where the electrostatic force that works to pull away from the fixed electrode is larger than the electrostatic force that works to attract the fixed electrode. . Thereby, for example, when both the first electrode part and the second electrode part are provided with the bulging part, the bulging part of the second electrode part is the first electrode rather than the bulging part of the first electrode part. When an electrostatic force is generated between the movable electrode and the fixed electrode while being positioned on the base end side of the portion, the movable electrode can be reliably separated from the fixed electrode.

  In this case, it is preferable to further include holding means for holding the movable electrode at a position stopped by the stopping means. Thereby, the situation where a movable electrode moves by a vibration etc. from the position stopped by the stop means can be prevented.

  The optical switch of the present invention includes a substrate having an optical path, a movable electrode supported by the substrate and having a mirror that reflects light passing through the optical path, a fixed electrode, and an electrostatic force between the movable electrode and the fixed electrode. The movable electrode is provided with a plurality of first electrode portions arranged in a comb shape, and the fixed electrode is disposed in a comb shape and inserted between the first electrode portions. A plurality of second electrode portions are provided, and the first electrode portion is provided with a bulging portion.

  According to such an optical switch, the movable electrode and the fixed electrode as described above are provided, and the mirror is fixed to the movable electrode. It is possible to reciprocate between a position where light passing through the pair passes through a pair of movable electrode and fixed electrode. Therefore, a small and highly integrated optical switch can be realized.

  An optical device according to the present invention includes a plurality of the optical switches described above. Since such an optical device includes the above-described optical switch, it can be downsized and highly integrated.

  According to the present invention, by providing the bulging portion at least in the electrode portion provided on the movable electrode among the movable electrode and the fixed electrode, the movable electrode is pulled and pulled away from the fixed electrode without the need for another electrode. be able to. Accordingly, it is possible to provide an electrostatic actuator, an optical switch, and an optical device that are small and can be highly integrated.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic plan view showing an optical switch provided with an electrostatic actuator according to an embodiment of the present invention, and FIG. 2 is a side view thereof. FIG. 1 shows a state in which a substrate P of an actuator structure 5 to be described later is omitted.

  In FIG. 1, an optical switch 1 has a planar waveguide 2, and an optical waveguide 3 that forms substantially cross-shaped optical paths A to D is provided in the planar waveguide 2. The planar waveguide 2 is provided with a groove portion 4 connected to the optical paths A to D.

  On the planar waveguide 2, an actuator structure 5 formed by using a micro electro mechanical system (MEMS) technique is provided. The actuator structure 5 has a substrate P, and a beam-like member (movable electrode) 6 is fixed to the substrate P. The beam-like member 6 is supported on both ends in a state where the central portion is located in the groove portion 4. In addition, a plurality of electrode portions 7 arranged in a comb-teeth shape are provided on one side of the beam-like member 6.

  The actuator structure 5 has a fixed electrode 8 provided so as to face the beam-like member 6, and a portion of the fixed electrode 8 facing the electrode portion 7 of the beam-like member 6 has a comb-like shape. A plurality of electrode portions 9 that are arranged and inserted between the respective electrode portions 7 are provided.

Swelling portions 7a and 9a are provided on the outer peripheral surfaces of the electrode portions 7 and 9, respectively. The expanded portion 7a, 9a has a portion which projects approximately parallel to the support surface _S 6, _{S 9} of the electrode 7 and 9 in the beam member 6 and the fixed electrode 8, for example, diamond, The shape is rectangular, elliptical, trapezoidal, or the like. Note that the bulging portions 7a and 9a of the present embodiment are rhombuses. The bulging portions 7a and 9a are preferably provided at the tip portions of the electrode portions 7 and 9 from the viewpoint of reducing the length of the electrode portions 7 and 9 and reducing the size.

  A mirror 10 that reflects light passing on the optical path A toward the optical path B is fixed to the central portion of the beam member 6. The mirror 10 is configured to enter the groove 4 of the planar waveguide 2.

  The beam-like member 6, the mirror 10, and the fixed electrode 8 are preferably formed of Si having conductivity in order to reduce costs and facilitate manufacture. The surface of the mirror 10 is preferably coated with gold (Au), silver (Ag), aluminum (Al), or the like from the viewpoint of improving the reflectance.

  The beam-like member 6 and the fixed electrode 8 are connected via a voltage source 11, and a predetermined voltage is applied between the beam-like member 6 and the fixed electrode 8 by the voltage source 11, so that an electrostatic force is generated therebetween. Is generated. The beam-shaped member 6, the fixed electrode 8, and the voltage source 11 constitute an electrostatic actuator 18 according to this embodiment. The beam member 6 is attracted to the fixed electrode 8 in a state where the beam member 6 and the fixed electrode 8 are separated as shown in FIG. FIG. 3 is a view showing a state in which the beam-like member 6 is attracted to the fixed electrode 8.

  By using static electricity in this way, the beam-like member 6 can be driven with low power consumption. Further, by providing the beam member 6 and the fixed electrode 8 with electrode portions, a large electrostatic force can be generated even with a small applied voltage.

  A connecting member 12 extending in the longitudinal direction of the beam-like member 6 is connected to one end of the beam-like member 6. A portion of the connecting member 12 that is connected to the beam-like member 6 (the tip end side of the connecting member 12) has a shape curved in an arc shape. Further, the distal end portion of the connecting member 12 is connected to an anchor 13 that joins the planar waveguide 2 and the actuator structure 5. On the other hand, an auxiliary member 14 is provided at the base end portion of the connecting member 12 opposite to the connection side with the beam-like member 6, and the auxiliary member 14 is provided in the concave portion 15 provided in the planar waveguide 2. Engage and engage.

  In the optical switch 1 according to the present embodiment as described above, for example, when the mirror 10 is in a position (blocking position) where light passing through the optical path A is blocked (blocking position), the initial state is set. 10 is moved to a position (passing position) through which light passing on the optical path A passes, a voltage is applied between the beam-like member 6 and the fixed electrode 8 to generate an electrostatic force. Then, as shown in FIG. 3, the beam-shaped member 6 is drawn toward the fixed electrode 8 side, and the mirror 10 moves to the passing position. At this time, the auxiliary member 14 moves in the concave portion 15 as the connecting member 12 moves, and comes into contact with the inner wall of the concave portion 15 and stops. Along with this, the movement of the beam-like member 6 is stopped. Then, by holding the auxiliary member 14 in this state, the beam-shaped member 6 is moved to the position in a state where compressive stress is generated in the beam-shaped member 6 after the mirror 10 is moved from the initial state to the passing position. Hold. As a result, the mirror 10 can be stably held at the position after the movement without continuously applying a voltage between the beam-like member 6 and the fixed electrode 8. Therefore, the position shift of the mirror due to vibration or the like is prevented.

  Here, with reference to FIG.4 and FIG.5, the mechanism in which the beam-shaped member 6 moves is demonstrated. 4 is an enlarged view of the region M shown in FIG. 1, and FIG. 5 is an enlarged view of the region N shown in FIG.

First, the case where the beam-like member 6 is attracted to the fixed electrode 8 will be described. First, a predetermined voltage is applied between the beam-shaped member 6 and the fixed electrode 8 by the voltage source 11 in a state where the beam-shaped member 6 and the fixed electrode 8 are separated as shown in FIG. Then, as shown in FIG. 4, on the swollen portion 7a and the protruding portion 9a works is the electrostatic force F _1, the bulging portion 7a and the protruding portion 9a mutually attracted. As a result, the movable beam-like member 6 moves toward the fixed electrode 8.

At this time, the voltage from the voltage source 11 is applied instantaneously, for example. As a result, the beam-like member 6 moves toward the fixed electrode 8 due to inertia even when no voltage is applied, and then stops at a desired position by the action of the connecting member 12 (see FIG. 5). Thus, since the voltage source 11 may be applied instantaneously, an extremely small voltage is sufficient. By the way, when the voltage from the voltage source 11 is continuously applied, the electrostatic force F ₁ in a state where the bulging portion 7a and the bulging portion 9a are closest to each other, that is, in a state where the bulging portion 7a and the bulging portion 9a are in parallel. Is balanced in the direction parallel to the support surfaces S ₆ and S _9, and the movement of the beam-like member 6 is stopped. Therefore, the application by the voltage source 11 stops before at least the bulging part 7a and the bulging part 9a are in the closest state.

The desired stop position of the fixed electrode 8 works so as to draw the beam-shaped member 6 toward the fixed electrode 8 when a predetermined voltage is applied between the beam-shaped member 6 and the fixed electrode 8 in the state shown in FIG. towards the electrostatic force F ₂ acting as separate the beam member 6 than the electrostatic force F ₃ from the fixed electrode 8 is larger position.

When the beam-shaped member 6 is separated from the fixed electrode 8 from the state shown in FIG. 5, a predetermined voltage is again applied between the beam-shaped member 6 and the fixed electrode 8 by the voltage source 11. The electrode portions 7 and 9, respectively bulged portions 7a, because 9a is provided, as shown in FIG. 5, the electrostatic force F ₂ acting to separate the beam member 6 from the fixed electrode 8 acts. At this time, an electrostatic force F ₃ that acts to attract the beam-like member 6 to the fixed electrode 8 also acts on the bulging portion 7 a and the bulging portion 9 a. However, the beam member 6, as described above, since the direction of the electrostatic force F ₂ than the electrostatic force F ₃ is stopped to increase position, mutually attracted the bulge portion 7a and the protruding portion 9a. Therefore, if the holding state by the connecting member 12 is released, the beam-like member 6 moves so as to be separated from the fixed electrode 8, and the state shown in FIG.

  In this case, the voltage from the voltage source 11 may be applied instantaneously. As a result, the beam-like member 6 moves toward the fixed electrode 8 by inertia even when no voltage is applied, so that the voltage applied by the voltage source 11 can be very small. Further, the application by the voltage source 11 is stopped before at least the bulging portion 7a and the bulging portion 9a are in the closest state for the same reason as when the beam-like member 6 and the fixed electrode 8 are attracted.

As described above, according to the electrostatic actuator 18 according to the present embodiment, since the bulging portions 7 a and 9 a are provided in the electrode portions 7 and 9 of the beam-shaped member 6 and the fixed electrode 8, the beam-shaped member extends from the fixed electrode 8. the electrostatic force F ₂ direction of separating the 6 can be generated. Therefore, since the beam-like member 6 can be pulled and separated from the fixed electrode 8 without requiring another electrode, it is possible to achieve a small size and high integration.

  And since the optical switch 1 which concerns on this embodiment is provided with said electrostatic actuator 18, the space saving of the direction orthogonal to the extension direction of the beam-shaped member 6 can be achieved. Therefore, a small and highly integrated optical switch can be realized. Also, as shown in FIG. 6, a plurality of sets of optical paths are provided in the planar waveguide 30 and a plurality of actuator structures 5 are arranged in an array on the top of the planar waveguide 30 corresponding to the plurality of sets of optical paths. Is possible. As a result, a plurality of optical switches can be packaged in a small size, and high integration and multi-channeling are also possible.

FIG. 7 shows an example of an optical device including the above-described optical switch. In the optical device 40 shown in FIG. 7, a plurality of optical paths are provided in the planar waveguide 41, and a plurality of optical switches 1 are installed on the optical paths. The optical device 40, light from any of the input and output terminals X ₁ to X _4, Y ₁ to Y _4, by using the optical path switching by appropriately operating each optical switch 1, the desired input and output terminals X _{1 to} X ₄ and Y _{1 to} Y ₄ are reached. Since such an optical device 40 is configured by using the optical switch 1 described above, it is possible to achieve downsizing and high integration.

  The preferred embodiment of the present invention has been described in detail above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the extending direction of the electrode portion 7 and the electrode portion 9 is the same direction, but the height positions of the beam-like member 6 and the fixed electrode 8 are different as shown in FIG. The angle formed by the extending direction of the electrode portion 7 and the electrode portion 9 may be θ (0 ° <θ <180 °). 8A shows a state in which the beam-like member 6 and the fixed electrode 8 are separated from each other, and FIG. 8B shows a state in which the beam-like member 6 is attracted to the fixed electrode 8. .

  Further, the bulging part may be provided only in the electrode part (first electrode part) 7 of the beam-like member (movable electrode) 6. Thereby, size reduction and cost reduction of an electrostatic actuator can be achieved.

  Furthermore, although the optical switch of the above embodiment is a 2 × 2 switch, the present invention can also be applied to an ON / OFF switch, an m × n switch, or the like.

It is a schematic plan view which shows the optical switch provided with the electrostatic actuator which concerns on embodiment. It is a side view of the optical switch shown in FIG. It is a figure which shows the state by which the beam-shaped member was drawn near to the fixed electrode. It is an enlarged view of the area | region M shown in FIG. FIG. 4 is an enlarged view of a region N shown in FIG. 3. It is a figure which shows the state by which the optical switch shown in FIG. 1 was arrayed. An example of an optical device provided with the optical switch shown in FIG. 1 is shown. It is the schematic which shows the deformation | transformation aspect of the electrostatic actuator which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical switch, 2 ... Planar waveguide, 3 ... Optical waveguide, 4 ... Groove part, 5 ... Actuator structure, 6 ... Beam-shaped member (movable electrode), 7 ... Electrode part (1st electrode part), 7a ... Swelling Protruding part, 8 ... fixed electrode, 9 ... electrode part (second electrode part), 9a ... bulging part, 10 ... mirror, 11 ... voltage source, 12 ... connecting member (holding means), 14 ... auxiliary member (stopping means) ), 15... Recess (stopping means), 18. Electrostatic actuator, 30. Planar waveguide, 40.

Claims (6)

A movable electrode;
A fixed electrode;
Means for generating an electrostatic force between the movable electrode and the fixed electrode;
The movable electrode is provided with a plurality of first electrode portions arranged in a comb shape,
The fixed electrode is provided with a plurality of second electrode portions arranged in a comb shape and inserted between the first electrode portions,
An electrostatic actuator, wherein the first electrode portion is provided with a bulging portion.   The electrostatic actuator according to claim 1, wherein the bulging portion is provided at a tip portion of the first electrode portion.   Stop means for stopping the movable electrode that moves so as to be attracted to the fixed electrode at a position where the electrostatic force that works to pull away from the fixed electrode is larger than the electrostatic force that works to attract the fixed electrode. The electrostatic actuator according to claim 1 or 2.   4. The electrostatic actuator according to claim 3, further comprising holding means for holding the movable electrode at a position stopped by the stopping means. A substrate having an optical path;
A movable electrode supported by the substrate and fixed with a mirror that reflects light passing through the optical path;
A fixed electrode;
Means for generating an electrostatic force between the movable electrode and the fixed electrode;
The movable electrode is provided with a plurality of first electrode portions arranged in a comb shape,
The fixed electrode is provided with a plurality of second electrode portions arranged in a comb shape and inserted between the first electrode portions,
An optical switch, wherein the first electrode portion is provided with a bulging portion.   An optical device comprising a plurality of optical switches according to claim 5.

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