Matrix-relay

TECHNICAL FIELD

The present invention relates to matrix relays 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.

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 7-294.73. 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 the object to provide a subminiature matrix relay that can be easily assembled.

EP-A2-0 709 911 discloses a single micromechanical switch in which the fixed contacts are arranged on the top surface of a substrate.

DISCLOSURE OF THE INVENTION

In order to achieve the aforementioned object, a matrix relay according to the invention is as defined in claim 1.

In an embodiment the driving means is a piezoelectric element laminated on one surface of the thin plate-shaped substrate.

In an another embodiment, the driving means is comprised of a heater layer formed on one surface of the thin plate-shaped substrate.

In an another embodiment, the driving means is comprised of a heater layer formed on one surface of the thin plate-shaped substrate and a driving layer formed by laminating a metal material on the heater layer via an insulating film.

Further embodiments are the subject-matters of claims 5-8.

BRIEF DESCRIPTION OF THE DRAWINGS

<ul id="ul0001" list-style="none" compact="compact"><li>Fig. 1A is a plan view showing an embodiment of a matrix relay;</li><li>Fig. 1B is a sectional view taken along the line 39B-39B in Fig. 1A;</li><li>Fig. 2 is a sectional view taken along the line 40-40 in Fig. 1A;</li><li>Fig. 3A is a matrix circuit diagram showing the circuit of the matrix relay of Fig. 1A and Fig. 1B;</li><li>Fig. 3B is a circuit diagram redrawn for providing a better view of Fig. 41A;</li><li>Fig. 4A is a plan view showing a matrix relay according to a second embodiment of the present invention;</li><li>Fig. 4B is a sectional view taken along the line 42B-42B in Fig. 4A;</li><li>Fig. 5 is a sectional view taken along the line 43-43 in Fig. 4A;</li><li>Fig. 6 is a perspective view of a third embodiment showing a number of movable pieces arranged in parallel for constituting a matrix relay;</li><li>Fig. 7 is a circuit diagram of a matrix relay according to a fourth embodiment, constructed of a number of relay elements;</li></ul>

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described next with reference to the accompanying drawings of Fig. 1 through Fig. 7.

The matrix relays of the first through fourth embodiments for achieving the second object will be described next with reference to the accompanying drawings of Fig. 1A through Fig. 7.

As shown in Fig. 1A and Fig. 3B, the first embodiment is a matrix relay formed by successively laminating a movable piece unit 120 and a cover 140 on a base 110 and connecting and integrating them with one another.

The base 110 is obtained by arranging parallel four shallow grooves 111, 112, 113 and 114 at a specified pitch on the upper surface of a silicon wafer 110a.

The movable piece unit 120 is obtained by arranging in an insulated state parallel first, second, third and fourth movable pieces 121, 122, 123 and 124 extended over a rectangular frame-shaped silicon wafer 120a. The first, second, third and fourth movable pieces 121, 122, 123 and 124 are formed by laminating an insulating film 126 on the upper surface of a monocrystal thin plate-shaped substrate 125 and further successively laminating a lower electrode 127, a piezoelectric element 128 and an upper electrode 129. In the center portion of the insulating film 126 is arranged a movable contact 130 in an insulated state.

Then, by stacking the movable piece unit 120 on the base 110 and connecting and integrating them with each other, the first, second, third and fourth movable pieces 121, 122, 123 and 124 are positioned above the shallow grooves 111, 112, 113 and 114, and their both ends are fixed and supported to the opening edge portions of the base 110.

The lower electrode 127, the piezoelectric element 128 and the upper electrode 129 are illustrated as if they were separated apart by the movable contact 130 in Fig. 39B, however, the lower electrodes 127, piezoelectric elements 128 and upper electrodes 129 located on the left-hand and right-hand sides are electrically connected to the respective counterparts.

The cover 140 is formed by arranging at a specified pitch parallel deep grooves 141, 142, 143 and 144 that become the inner spaces, on the lower surface of a glass wafer 140a and providing a pair of fixed contacts 145 and 146 on the ceiling surfaces of the deep grooves 141, 142, 143 and 144 in positions corresponding to the movable contacts 130.

The fixed contacts 145 are connected to the respective through holes 161a, 162a, 163a and 164a provided on the glass wafer 140a via printed wiring lines (not shown) along the lower surface of the glass wafer 140a and led to the surface of the cover 140.

Likewise, the fixed contacts 146 are connected to the respective through holes 161b, 162b, 163b and 164b provided on the glass wafer 140a via printed wiring lines 151, 152, 153 and 154 formed along the lower surface of the glass wafer 140a and made to be electrically connectable on the surface of the cover 140.

Then, the through holes 161a and 162a are electrically connected to an input use first connecting pad 170 via a printed wiring line 155, while the through holes 163a and 164a are electrically connected to an input use second connecting pad 171 via a printed wiring line 156. Further, the through holes 161b and 163b are electrically connected to an output use first connecting pad 172 via a printed wiring line 157. The through holes 162b and 164b are electrically connected to an output use second connecting pad 173 via a printed wiring line 158.

The four lower electrodes 127 are electrically connected to a driving use common through hole 180 provided at the cover 140. On the other hand, the four upper electrodes 129 are electrically connected to driving use through holes 181, 182, 183 and 184 provided at the cover 140.

Therefore, inputs 1 and 2 and outputs 1 and 2 in the circuit diagrams of Figs. 3A and 3B correspond to the connecting pads 170 and 171 and the connecting pads 172 and 173, respectively.

Ry 1, 2, 3 and 4 in Figs. 3A and 3B correspond to the relays constructed of the aforementioned first, second, third and fourth movable pieces 121, 122, 123 and 124, respectively.

The operation of the matrix relay having the above-mentioned construction will be described next.

First, if no voltage is applied to the lower electrode 127 of the first movable piece 121 and the upper electrode 129, then the piezoelectric element 128 is not excited, when the first movable piece 121 remains flat and the movable contact 130 is separated from the fixed contacts 145 and 146.

If a voltage is applied via the driving use common through hole 180 and the driving use through hole 181 so that the piezoelectric element 128 curves upward, then the first movable piece 121 curves upward against the spring force of the thin plate-shaped substrate 125. By this operation, the movable contact 130 comes in contact with the fixed contacts 145 and 146, and the connecting pads 170 and 172 continue each other from the through holes 161a and 161b via the printed wiring line 155 and 157.

Further, if the aforementioned voltage application is released, then the first movable piece 121 is restored into the original state by the spring force of the thin plate-shaped substrate 125, and the movable contact 130 separates from the fixed contacts 145 and 146.

Subsequently, if a voltage is applied similarly via the through holes 180 and 182 so that the piezoelectric element 128 of the second movable piece 122 curves upward, then the second movable piece 122 curves upward. By this operation, the movable contact 130 comes in contact with the fixed contacts 145 and 146, and the connecting pads 170 and 173 continue each other from the through holes 162a and 162b via the printed wiring line 155 and 158.

If a voltage is applied via the through holes 180 and 183 so that the piezoelectric element 128 of the third movable piece 123 curves upward, then the third movable piece 123 curves upward. By this operation, the movable contact 130 comes in contact with the fixed contacts 145 and 146, and the connecting pads 171 and 172 continue each other from the through holes 163a and 163b via the printed wiring line 156 and 157.

Further, if a voltage is applied via the through holes 180 and 184 so that the piezoelectric element 128 of the fourth movable piece curves upward, then the fourth movable piece 124 curves upward. By this operation, the movable contact 130 comes in contact with the fixed contacts 145 and 146, and the connecting pads 171 and 173 continue each other from the through holes 164a and. 164b via the printed wiring line 156 and 158.

Although the aforementioned first embodiment has been described on the basis of the use of the normal piezoelectric element 128 that is restored into the original state upon the release of the application voltage. However, the present invention is not always limited to this, and it is acceptable to use a shape memory piezoelectric element that retains the deformed state even when the application voltage is released and is restored into the original state when a voltage is applied in the opposite direction, for the provision of the so-called latching type matrix relay.

As shown in Fig. 4A, Fig. 4B and Fig. 5, the second embodiment is almost similar to the aforementioned first embodiment, and a point of difference is that a deformation by virtue of the thermal expansion of the first, second, third and fourth movable pieces 121, 122, 123 and 124 is utilized in contrast to the first embodiment that utilizes the deformation of the piezoelectric element 28.

That is, the first, second, third and fourth movable pieces 121, 122, 123 and 124 are constructed of a heater layer 131 whose electrical resistance is increased by injecting boron or the like into the surface of the thin plate-shaped substrate 125 made of a monocrystal and a driving layer 133 that is formed by laminating a metal material via an insulating film 132. Then, a movable contact 130 is arranged in an insulated state in the center portion of the insulating film 132.

The operation of the matrix relay of the second embodiment will be described next.

For example, as shown in Fig. 4A and 4B, if no current is flowing through the heater layer 131 of the third movable piece 123, then the heater layer 131 does not generate heat, and therefore, the driving layer 133 does not expand. For this reason, the first movable piece 121 remains flat, and the movable contact 130 thereof is separated from the fixed contacts 145 and 146.

If a current is made to flow through the heater layer.131 via the driving use common through hole 180 and the driving use through hole 183, then the heater layer 131 generates heat, thereby heating the thin plate-shaped substrate 125 and the driving layer 133. However, the coefficient of thermal expansion of the driving layer 133 is much larger than the coefficient of thermal expansion of the thin plate-shaped substrate 125, and therefore, the third movable piece 123 curves upward against the spring force of the thin plate-shaped substrate 125. By this operation, the movable contact 130 comes in contact with the fixed contacts 145 and 146. Consequently, the connecting pads 170 and 172 continue each other from the through holes 163a and 163b via the printed wiring lines 156 and 157.

Further, if the aforementioned voltage application is released, then the third movable piece 123 is restored into the original state against the spring force of the thin plate-shaped substrate 125, and the movable contact 130 separates from the fixed contacts 145 and 146.

It is to be noted that the operations of the other first, second and fourth movable pieces 121, 122 and 124 are similar to those of the first embodiment, and therefore, no description is provided for them.

Each movable piece may be formed of only the heater layer as the driving means. Furthermore, the heater layer may be formed by laminating a metal material of platinum, titanium or the like or a polysilicon on the surface of the thin plate-shaped substrate.

Although the aforementioned embodiment has been described on the basis of the matrix relay in which the four movable pieces are arranged parallel, the present invention is not always limited to this. As shown in Fig. 6 of the third embodiment or Fig. 7 of the fourth embodiment, it is, of course, acceptable to apply the present invention to a matrix relay in which more than four movable pieces are arranged parallel. As a connecting method of the fixed contacts in this case, there is, for example, a connection method with a print wiring of a multilayer structure formed on the surface of the cover via through holes provided at the cover.