Electrical generator or motor structure – Non-dynamoelectric – Charge accumulating
Reexamination Certificate
2002-09-13
2004-08-10
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Charge accumulating
Reexamination Certificate
active
06774533
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a micro-actuator and in particular to a microactuator using an electrostatic impact driving mechanism, and to a method of making such a microactuator.
BACKGROUND ART
Precision positioning techniques required in carrying out a micromachining or a micro-displacement operation has come to be ranked to take a very important position, and are sought to be higher in precision than ever.
Making good use of micromachining technologies for manufacturing a positioning device allows its bulk production in a batch process, and has an advantage of eliminating the need to assemble each device product individually while yielding products small-sized, at a low cost and with a reduced individual difference. For this reason, recent years have seen extensive researches conducted on various microactuators and microsystems for positioning (see M. Steven Rodger et al, “Intricate Mechanisms-on-a-chip Enabled by 5-Level Surface Micro Machining”, Digest of Transducers '99, Sendai, Japan, June 1999, pp. 990-993). Faced with the problem of importance that the force produced is unsatisfactory and that the movable distance is insufficient, however, micro-actuators so far proposed have had a limited extent of their applicability. For example, an impact driving mechanism using a piezoelectric element has been proposed (see Toshiro Higuchi, Masahiro Watanabe, Ken-ichi Watanabe, “Ultra-precision Positioning Mechanism utilizing Rapid Deformation of a Piezoelectric Element”, Journal of the Society of Precision Engineering, 54-11, 2107 (1998), which using a frictional force and an piezoelectric element, has both a very small displacement in a nanometer range and a movable distance utmost minimum in principle, but needs to be built up individually and has a limitation in miniaturization.
Further, microactuators so far proposed are poor in reliability measure such as to prevent entry of dust and moisture in air and are thus inferior in environmental reliability.
It is accordingly a first object of the present invention to provide a microactuator that eliminates the need to assemble individually and can be miniaturized much more than ever and, in particular, to provide a self-moved impact driven actuator which with an electrostatically driven, movable mass member in its driving source is high in environmental reliability. It is a second object of the present invention to provide a method of making such a microactuator utilizing a bulk micromachining technique.
DISCLOSURE OF THE INVENTION
In order to achieve the first object mentioned above, there is provided in accordance with the present invention a microactuator with an electrostatic impact driving mechanism, which as set forth in claim
1
in the appended claims comprises: a closed receptacle formed of an outer frame part, a pedestal part and a lid part; an elastic support beam member disposed in the said closed receptacle; a fixing member disposed in the said closed receptacle and securely connecting a first end of the said elastic support beam member to the said pedestal part; a movable mass member disposed in the said closed receptacle and securely connected to a second end of the said elastic support beam member; a driving electrode and a stopper member disposed in the said closed receptacle, each of which is securely connected to the said pedestal part and spacedly juxtaposed with the said movable mass member; and a power supply circuit disposed in the inside or the outside of the said closed receptacle for applying a voltage between the said movable mass and driving electrode members, wherein the microactuator is so operable that turning the said power supply circuit ON generates electrostatic attraction between the said driving electrode and movable mass members, thereby bringing the said movable member into collision with the said stopper member, followed by the transmission of a kinetic energy then produced to the said closed receptacle, and subsequently turning the said power supply circuit OFF removes the said electrostatic attraction, thereby permitting the said movable mass member to return to its original position under an elastic force exerted by the said elastic support beam member, followed by the transmission of a reaction force then produced to the said closed receptacle, whereby an entire body of the said microactuator is moved in a given direction.
The microactuator so constructed with the electrostatic driving mechanism is of a structure that can be built up by an integrated circuit process technology, and which permits the components to be integrated into an identical device, which eliminates the need to fabricate individual components, and which allows the product to be made that is extremely small in size
Specifically, the microactuator with the electrostatic impact driving mechanism may as set forth in claim
2
in the appended claims be characterized in that the said first end of the said elastic support beam member is securely connected to a single fixing element constituting the said fixing member, the said movable mass member is securely connected to the said second end of the said elastic support beam member at two places thereon, the said single fixing element is disposed so as to make the said movable mass member capable of rocking over a surface of the said pedestal part, the said driving electrode and stopper members comprise a first and a second driving electrode and a first and a second stopper member, wherein the said first driving electrode and stopper element are each disposed in front of the said movable mass member while the said second driving electrode and stopper elements are each disposed in rear of the said movable mass member, and the said voltage is applied between a said driving electrode and the said movable mass member via the said outer frame part.
In this construction of the microactuator, selecting the first or second drive electrode with which the voltage is applied allows the microactuator to be bodily moved forth or back.
Alternatively, the microactuator with the electrostatic impact driving mechanism may as set forth in claim
3
in the appended claims be characterized in that the said elastic support beam member is capable of elastically supporting the said movable mass member in two axial directions perpendicular to each other, the said elastic support beam member has a pair of first ends securely connected, respectively, to two fixing elements constituting the said fixing member, the said second end of the said elastic support beam member is securely connected at one place to the said movable mass member, the said two fixing elements are arranged so as to make the said movable mass member capable of rocking forth and back and right and left over a surface of the said pedestal part, the said driving electrode and said stopper members comprise a first, a second, a third and a fourth driving electrode and a first, a second, a third and a fourth stopper element, wherein the said first driving electrode and stopper member, the said second driving electrode and stopper member, the said third driving electrode and stopper element and the said fourth driving electrode and stopper element are disposed in front of, in rear of, at a right hand side and at a left hand side, of the said movable mass member, respectively, and the said voltage is applied between a said driving electrode and the said movable mass member via the said outer frame part.
This construction permits the microactuator to be bodily moved two dimensionally in a given plane and to be so moved in any direction as desired.
Alternatively, the microactuator with the electrostatic impact driving mechanism may as set forth in claim
4
in the appended claims be characterized in that the said movable mass member is fan-shaped and securely connected to the said second end of the said elastic support beam member, the said first end of said elastic support beam member is securely connected to the said fixing member, the said fixing member is arranged so as to make the said movable mass member capable
Fujita Hiroyuki
Kobayashi Dai
Mita Makoto
Tensaka Shouichi
Japan Science and Technology Agency
Tamai Karl
Westerman Hattori Daniels & Adrian LLP
LandOfFree
Electrostatic impact driving microactuator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electrostatic impact driving microactuator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrostatic impact driving microactuator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3339551