JP2005333048A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in which a conventional electrical fine machine device (MEMS) type actuator needs to have a larger driving arm when having a larger driving area, which causes upsizing. <P>SOLUTION: A driving arm 4 which constitutes an actuator 1 is made wider at its middle part than at both the ends, and driving electrodes 6 are provided at both ends of the driving arm 4. Consequently, an area for the driving electrodes 6 imparting a driving force is secured and the driving arm 4 is more flexible and bendable to expand a driving area. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an actuator used in an electronic device.

  A conventional electric micromechanical device (hereinafter referred to as MEMS) has an actuator that supports a drive arm serving as a drive unit of the actuator on a substrate, and a drive electrode provided on the drive arm (for example, a piezoelectric in a piezoelectric drive system). There is known a configuration in which the drive arm is controlled by applying a drive voltage to a drive electrode or an electrostatic electrode in an electrostatic drive system.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP 2000-188050 A

  Such MEMS actuators can be applied to switches for switching transmission / reception signals of mobile phones, switches for turning on / off optical signals, etc., and it is important to expand the drive area. It has become like this.

  However, since the drive area in the drive arm is determined by the amplitude of the drive arm, in order to expand the area, the drive arm has to be set long, and there is a problem that the actuator becomes large.

  Therefore, the present invention solves such a problem and provides an actuator having a large driving area.

  In order to achieve this object, in the present invention, in particular, the structure of the drive arm constituting the actuator is set such that the width of the drive arm is set to be narrower in the middle than both ends, and the drive electrodes are provided on both ends of the drive arm. It is.

  With this configuration, it is possible to secure the area of the drive electrode that applies a drive force to the drive arm and to give the drive arm flexure, and as a result, it is possible to expand the drive region of the actuator.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a switch 2 using an actuator 1 according to the present invention. The basic structure of the switch 2 is a plate-like drive arm supported by a substrate 3 and a pair of support portions 5 provided on the substrate 3 at both ends. 4, drive electrodes 6 provided at both ends of the lower surface of the drive arm 4, and connection electrodes 7 provided in the middle of the lower surface of the drive arm 4 to connect the electrodes provided on the substrate 3. Yes.

  Further, as shown in FIG. 2, the drive electrode 6 is configured by sandwiching the piezoelectric layer 9 between a pair of drive voltage application control electrodes 8a and 8b, and a drive voltage is applied between the control electrodes 8a and 8b. Application is based on the principle that the piezoelectric layer 9 expands and contracts and the drive arm 4 bends when applied. The voltage applying means for the control electrode may be appropriately connected using general connecting means such as wire bonding or inner layer wiring, and is not particularly shown in FIG.

  In addition, silicon is used as the material for the substrate 3 and the drive arm 4, but basically any surface having an insulating property may be used, and it is possible to replace a metal plate with an insulating treatment. is there.

  In addition, by providing the drive electrodes 6 on both end portions of the lower surface of the drive arm 4, it is possible to increase the drive force when the drive arm 4 is restored after being driven.

  When the drive arm 4 constituting the switch 2 is viewed, as shown in FIG. 3, the width is narrower at the middle side where the connection electrode 7 is provided than at both ends where the drive electrode 6 is provided. Is set to This is because the intermediate position of the drive arm 4 at which the amplitude in the drive arm 4 is maximized is narrower than the both end portions, so that bending occurs at the time of driving and the driving range can be increased correspondingly, and a driving electrode as a driving source is provided. Since the width of both ends of the drive arm 4 is wide, the area of the drive electrode that gives the drive force can be increased, and further, the drive electrode can be kept close to the support portion, so that a decrease in the drive force due to the deflection of the drive arm 4 can be suppressed. The drive area of the drive arm 4 can be expanded efficiently.

  In addition, since the drive arm 4 has a tapered shape that is continuously sandwiched from the support portion side that is both ends thereof toward the intermediate position, the step as shown by the broken line is not formed on the outer peripheral portion. Since the stress concentration with respect to the bending at the step portion can be suppressed, the durability of the drive arm 4 can be improved. Although not particularly illustrated, durability can be further improved by chamfering the curved portion at the boundary portion between the taper portion and the straight portion to obtain a curved shape.

  In the present embodiment, the drive electrode 6 is provided on the lower surface side of the drive arm 4, but may be provided on the upper surface side of the drive arm 4. In this case, the drive area can be further increased.

  The actuator according to the present invention has an effect that the drive area can be expanded, and is particularly useful in applications where a large drive area is required while being small.

The perspective view of the switch using the actuator in one embodiment of this invention Sectional drawing which shows the drive state of the switch Bottom view of the drive arm that composes the switch

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 2 Switch 3 Board | substrate 4 Drive arm 5 Support part 6 Drive electrode 7 Connection electrode 8a, 8b Control electrode 9 Piezoelectric layer

Claims (2)

A substrate having at least a surface insulated, a drive arm having both ends supported by a pair of support portions with respect to the substrate, and a drive electrode provided on the surface of the drive arm and applying a driving force to the drive arm The drive electrode is provided on both ends of the drive arm, and the width of the drive arm is set to be narrower in the middle than both ends. 2. The actuator according to claim 1, wherein the width of the drive arm is continuously narrowed from both ends toward the middle.

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