Electrical generator or motor structure – Non-dynamoelectric – Piezoelectric elements and devices
Reexamination Certificate
1999-02-26
2002-06-18
Dougherty, Thomas M. (Department: 2834)
Electrical generator or motor structure
Non-dynamoelectric
Piezoelectric elements and devices
C310S307000, C310S348000, C310S311000
Reexamination Certificate
active
06407482
ABSTRACT:
TECHNICAL FIELD
The present invention relates to electronic components such as micro-relays, and in particular micro-relays, matrix relays and micro-relay chips having contacts which are opened and closed by curving a movable piece constructed of a monocrystal thin plate-shaped substrate.
BACKGROUND ART
Conventionally, as a relay, there has been, for example, an electromagnetic relay utilizing an electromagnet. However, the relay, which necessitates mechanical components, is hard to be reduced in size. Furthermore, the movable components of the mechanical components, which have great inertial forces, tend to disadvantageously cause fatigue failure and lack in durability.
There is otherwise existing a semiconductor switching device as a sort of small-sized relay, however, the device disadvantageously has a great resistance in turning on its contact, degraded frequency characteristics and a low insulating property between its input and output and between its terminals of an identical polarity.
In view of the aforementioned problems, the present invention has a first object to provide a subminiature micro-relay that has a small resistance in turning on its contact as well as the desired vibration resistance, frequency characteristics and insulating property.
Conventionally, as a matrix relay, there has been, for example, the one disclosed in the prior art reference of Japanese Patent Laid-Open Publication No. HEI 7-29473. The matrix relay is an electromagnet array comprised of a required number of electromagnets obtained by winding a solenoid around a fixed contact core, where the contacts are opened and closed by driving a movable spring contact provided on a strip.
However, the above-mentioned matrix relay has the electromagnet obtained by winding the solenoid around the fixed contact core as a component, and this puts a limit on compacting the device, and in particular, reduction in thickness.
Most of the components are not flat, meaning that they cannot be stacked in one direction, and this poses the problem that the assembling is troublesome and the productivity is low.
In view of the aforementioned problems, the present invention has a second object to provide a subminiature matrix relay that can be easily assembled.
Further, conventionally, as an electronic component of the micro-relay chip, there has been the one proposed in FIG. 27 and FIG. 28 of Japanese Patent Laid-Open Publication No. HEI 7-299765. That is, the electronic component is a micro-relay obtained by wire-bonding the connecting electrodes of a micro-relay chip to the external terminals of a lead frame and molding them with resin.
However, according to the above-mentioned electronic component, the whole body of the micro-relay chip has been molded with resin, and therefore, heat radiation is hard to be achieved. Therefore, due to the heat generation of the internal components, a malfunction tends to occur and the operating characteristics tend to vary.
The above-mentioned electronic component is required to individually connect by wire bonding each connecting electrode of the micro-relay chip to each external terminal formed on the lead frame. For this reason, there is a great number of working processes, and the productivity is low. Furthermore, wire disconnection tends to be caused by vibration or the like, and this poses the problem that the reliability is low.
In view of the aforementioned problems, the present invention has a third object to provide an electronic component that can prevent the malfunction and the variation in operating characteristics due to heat and has high productivity and reliability.
DISCLOSURE OF THE INVENTION
In order to achieve the aforementioned first object, the first feature of the present invention is a micro-relay characterized by providing a thin plate-shaped substrate comprised of a monocrystal with a driving means, supporting on a base both ends of a movable piece at least one surface of which is provided with at least one movable contact and curving the movable piece via the driving means, thereby bringing the movable contact in and out of contact with a fixed contact that faces the movable contact, for making and breaking an electric circuit.
According to the first feature of the present invention, the contacts can be opened and closed by curving the thin plate-shaped substrate constructed of the monocrystal, and therefore, the device can be easily compacted. Furthermore, the inertial force of the movable piece constructed of the thin plate-shaped substrate is small, and therefore, fatigue failure is hard to occur, so that a micro-relay having an excellent durability can be obtained.
The movable piece has its both ends supported, and therefore, a micro-relay that is hard to receive the influence of external vibration or the like and has stable operating characteristics can be obtained.
Furthermore, there can be obtained a micro-relay that has a very small resistance in turning on the contact as compared with the semiconductor switching element, high frequency characteristics and insulating properties between its input and output and between its terminals of an identical polarity.
A second feature is a micro-relay in which a device wafer is connected and integrated with an opening edge portion of a box-shaped base comprised of a handle wafer via an insulating film, and the movable piece is formed by cutting a pair of slits through the device wafer.
According to the second feature, the movable piece is formed on the device wafer connected and integrated with the box-shaped base of the handle wafer. This arrangement allows the manufacturing processes to be wholly achieved by the semiconductor manufacturing techniques.
The handle wafer and the device wafer are connected and integrated with each other via the insulating film, and therefore, the wafers can be connected and integrated with each other at a temperature lower than in directly connecting and integrating silicon objects. For this reason, a material having a low melting point can be used for the fixed contact and the movable contact, allowing the degree of freedom of design to be expanded.
A third feature is a micro-relay in which the device wafer is formed with a connecting use opening portion in a position opposite to a connecting pad of the fixed contact provided on a bottom surface of the handle wafer.
According to the third feature, connection to the outside can be achieved by utilizing wire bonding via the connecting use opening portion provided at the device wafer. This allows the wiring structure of the micro-relay itself to be simplified for easy manufacturing.
A fourth feature is a micro-relay in which the inside surface of the connecting use opening portion is covered with an insulating film.
According to the fourth feature, the inside surface of the connecting use opening portion is covered with an insulating film. Therefore, even when wire bonding is performed, the wire is not brought in contact with the silicon layer, and it is not interfered by the driving use power source.
A fifth feature is a micro-relay in which a cooling fin is formed on the upper surface of the device wafer.
According to the fifth feature, heat generated from the movable piece speedily dissipates to the outside via the cooling fin formed on the upper surface of the device wafer. This improves the operating characteristics in the restoration stage.
Even when micro-relays are integrated with each other, the cooling fin efficiently radiates heat, so that malfunction due to overheat can be prevented.
A sixth feature is a micro-relay in which the movable piece is previously curved and urged so as to bring a movable contact provided on its one surface in contact with a fixed contact that faces the movable contact.
According to the sixth feature, the thin plate-shaped substrate is previously curved to bring the movable contact in contact with the fixed contact, and therefore, a self-retaining type micro-relay can be obtained, allowing the power consumption to be remarkably reduced.
A seventh feature is a micro-relay in which a pair of
Fujiwara Teruhiko
Nakajima Takuya
Sakata Minoru
Seki Tomonori
Dougherty Thomas M.
Morrison & Foerster / LLP
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