JP2000266231A - Semiconductor microvalve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor microvalve allowing low power consumption. SOLUTION: A valve port 10a is penetratedly provided on a silicon substrate 10. A flexible portion 22 is provided with a movable piece 22a comprising silicon provided with a valve element 23 at a center portion and the movable piece 22a constitutes a first bimetal element. A second bimetal element 24 is laminated on a predetermined position between the valve element 23 and a peripheral portion 22c in the movable piece 22a through an insulation layer 26. A bimetal is constituted by the first bimetal element and the second bimetal element 24. A wiring 27b as an energization means for only energizing to the second bimetal element 24 is connected to the bimetal element 24. An insulation layer 26 interposed between the first bimetal element and the second bimetal element 24 electrically and thermally insulates the first bimetal element from the second bimetal element 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor microvalve used for controlling a flow rate of a fluid such as a gas.

[0002]

2. Description of the Related Art Conventionally, a semiconductor microvalve having a configuration shown in FIG. 3 has been proposed as a semiconductor microvalve used for controlling a flow rate of a fluid such as a gas. The semiconductor microvalve shown in FIG. 3 is a normally-open type valve, and has a valve port 10a formed of a through hole penetrating from one surface (upper surface in FIG. 3) in the thickness direction to the other surface (lower surface in FIG. 3). And a valve body 23 that opens and closes a valve port 10a at the center and a peripheral portion 22c
And a flexible portion 22 which is connected to the one surface side via a spacer 30 and has flexibility. In addition, a flow hole (not shown) through which a fluid passes is formed at a key point of the flexible portion 22. The communication hole communicates with the valve port 10a when the valve port 10a is opened by the valve element 23.

The flexible portion 22 includes a movable piece 22a made of silicon and provided with a valve body 23 at a central portion.
In FIG. 5A, a diffusion resistance layer 25 is formed at a predetermined portion between the valve element 23 and the peripheral portion 22c. The diffusion resistance layer 25 is connected to a wiring 27a for supplying a current to the diffusion resistance layer 25. Here, the movable piece 22a constitutes a first bimetal element, and the second bimetal element 24 is laminated on the diffusion resistance layer 25 via an insulating layer 26 '. The second bimetal element 24 is formed of a material having a different coefficient of thermal expansion from the first bimetal element. That is, the flexible portion 22 is formed of a bimetal by the first bimetal element and the second bimetal element 24, and bends in response to a temperature change. As is well known, bimetals are formed by bonding metal plates having different coefficients of thermal expansion, and when both metal plates are heated to the same temperature, the lengths of the two metal plates differ. The two metal plates are curved in an arc with the shorter metal plate inside.

In the semiconductor microvalve shown in FIG. 3, when the valve port 10a is closed by the valve body 23,
By energizing the diffusion resistance layer 25 to generate heat, the temperature of the bimetal is raised and curved.
The insulating layer 26 'is a layer for providing electrical insulation between the diffusion resistance layer 25 and the second bimetal element 24, and prevents heat conduction from the diffusion resistance layer 25 to the second bimetal element 24. Not be insulated (not insulated)
The thickness has been reduced.

[0005]

By the way, in the above-mentioned conventional semiconductor microvalve, in order to increase the amount of displacement of the valve element 23, the power supplied to the diffusion resistance layer 25 for bending the bimetal is increased. The temperature of the bimetal needs to be raised higher. However, in the conventional semiconductor microvalve, the diffusion resistance layer 2
5, the temperature of the second bimetal element 24 is also increased by heating, so that the bimetal is more curved (to increase the displacement of the valve element 23), the diffusion resistance layer 25 and the second bimetal It is necessary to raise the temperature of both the element 24 and there is a problem that power consumption is increased.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a semiconductor microvalve capable of reducing power consumption.

[0007]

According to a first aspect of the present invention, there is provided a semiconductor substrate in which a valve port is formed from one surface in a thickness direction to another surface, and an end on the one surface side of the semiconductor substrate. A flexible portion to which a portion is attached and has flexibility;
A valve element provided on the flexible portion for opening and closing the valve port on the one surface side of the semiconductor substrate; a first bimetal element and a second bimetal element provided on the flexible portion and made of materials having different thermal expansion coefficients from each other A bimetal element laminated via an insulating layer that electrically and thermally insulates the two bimetal elements from each other, and energizing means for energizing only one of the first bimetal element and the second bimetal element. By energizing only one of the first bimetal element and the second bimetal element to increase the temperature of only the energized one, Since the difference in length between the first bimetal element and the second bimetal element can be made larger than in the conventional case where the temperature of both bimetal elements rises, the amount of displacement of the valve element can be reduced. Compared able to large and dealt with in a power for raising the temperature of either one of the first bimetallic element and a second bimetallic element, it is possible to reduce power consumption.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic structure of a semiconductor microvalve according to this embodiment is substantially the same as the conventional structure shown in FIG. 3, and as shown in FIG. 1, from one surface in the thickness direction (the upper surface in FIG. 1). A silicon substrate 10 having a valve port 10a formed of a through-hole penetrating over the other surface (the lower surface in FIG. 1), and a valve element 23 for opening and closing the valve port 10a provided at a central portion and a peripheral portion (end portion) 22c. Is provided with a flexible portion 22 which is connected to the one surface side of the silicon substrate 10 via a spacer 30 and has flexibility. Here, in the silicon substrate 10, a valve seat 13 with which the valve body 23 of the flexible portion 22 comes in contact with or separates from the periphery of the valve port 10 a is continuously and integrally provided in the thickness direction of the silicon substrate 10. In addition, a flow hole (not shown) through which a fluid passes is formed at a key point of the flexible portion 22.
The communication hole communicates with the valve port 10a when the valve port 10a is opened by the valve element 23.

The flexible portion 22 has a movable piece 22a made of silicon and provided with a valve body 23 at the center, and the movable piece 22a constitutes a first bimetal element. On a predetermined portion between the valve element 23 and the peripheral portion 22c of the movable piece 22a, a second bimetal element 2 is provided via an insulating layer 26.
4 are stacked. The second bimetal element 24 is formed of a material having a different coefficient of thermal expansion from the first bimetal element. That is, the flexible portion 22 is formed of a bimetal by the first bimetal element and the second bimetal element 24, and bends in response to a temperature change.

In the present embodiment, a wiring 27b is connected to the bimetal element 24 as an energizing means for energizing only the second bimetal element 24, and the first bimetal element and the second bimetal element 24 are connected to each other. The insulating layer 26 interposed between the first bimetal element and the second
For electrical and thermal insulation from the bimetal element 24. In short, the insulating layer 26 is
Has a function of preventing heat generated in the bimetal element 24 from being conducted to the first bimetal element.

Therefore, in the semiconductor microvalve of the present embodiment, when the valve port 10a is closed by the valve element 23, the bimetal element 24 is energized to generate heat only in the second bimetal element 24, so that the bimetal is removed. Curve.

Here, the difference in the amount of bending between the bimetal of the present embodiment and the conventional bimetal shown in FIG. 3 will be described with reference to the schematic diagram shown in FIG. Now
As shown in FIG. 2A, the bimetal has a first metal plate 4A (corresponding to the first bimetal element) and a second metal plate 4B (corresponding to the second bimetal element 24) having different coefficients of thermal expansion. And are formed by bonding together. When bending such a bimetal, in the conventional configuration,
Since the temperature of the entire bimetal rises, the lengths of both metal plates 4A and 4B become longer (both metal plates 4A and 4B thermally expand) as shown in FIG. Since the lengths of the two metal plates 4A and 4B are different from each other, as shown in FIG.
Are curved in an arc shape.

On the other hand, in the present embodiment, the temperature of only the second metal plate 4B (corresponding to the second bimetal element 24) rises, so that the second metal plate 4B as shown in FIG. As shown in FIG. 2E, only the length of the plate 4B increases (only the second metal plate 4B thermally expands) and the lengths of the two metal plates 4A and 4B differ. Both metal plates 4A and 4B are curved in an arc shape with the shorter metal plate 4A inside.

By the way, focusing on the second metal plate 4B, when the temperature of the second metal plate 4B is raised to the same temperature in the conventional configuration and the present embodiment, the first embodiment is the first metal plate. The difference in length between the plate 4A and the second metal plate 4B can be increased (see FIGS. 2B and 2D).

Thus, in the present embodiment, only the second bimetal element 24 of the first bimetal element and the second bimetal element 24 is energized to raise the temperature of only the second bimetal element 24. Since the length difference between the first bimetal element and the second bimetal element 24 can be increased as compared with the case where the temperature of both bimetal elements rises as in the related art,
The amount of displacement of the valve body 23 can be made larger than in the past, and moreover, only power for raising the temperature of the second bimetal element 24 is sufficient, so that low power consumption can be achieved.

In the present embodiment, only the second bimetal element 24 is energized. However, it is a matter of course that a configuration in which only the first bimetal element is energized may be adopted. .

[0017]

According to the first aspect of the present invention, there is provided a semiconductor substrate having a valve opening formed from one surface to the other surface in a thickness direction, and a flexible portion having an end attached to the one surface of the semiconductor substrate and having flexibility. A valve body provided on the flexible portion for opening and closing the valve port on the one surface side of the semiconductor substrate; a first bimetallic element provided on the flexible portion and made of materials having different thermal expansion coefficients from each other; Energizing means for energizing only one of the first bimetal element and the second bimetal element, and a bimetal in which the bimetal element is laminated via an insulating layer electrically and thermally insulating between the two bimetal elements; Therefore, by energizing only one of the first bimetal element and the second bimetal element to raise the temperature of only the energized one, the first bimetal element The difference between the lengths of the two bimetal elements can be made larger than in the conventional case where the temperature of both bimetal elements rises, so that the displacement of the valve body can be made larger than in the conventional case. In addition, since power for raising the temperature of only one of the first bimetal element and the second bimetal element is sufficient, power consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment.

FIG. 2 is a schematic diagram for explaining an operation of a main part of the above.

FIG. 3 is a schematic sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Silicon substrate 10a Valve port 13 Valve seat 22 Flexible part 22a Movable piece 23 Valve element 24 Second bimetal element 26 Insulating layer 27b Wiring

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hitoshi Yoshida 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. (72) Inventor Hiroshi Kawada 1048 Odaka Kadoma Kadoma City Osaka Prefecture Matsushita Electric Works Co., Ltd. ( 72) Inventor Keiko Fujii 1048 Kadoma, Kazuma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. 3H057 AA16 BB07 BB41 CC06 DD12 EE10 FA15 FA23 FB13 FC02 FD19 HH05

Claims (1)

[Claims] 1. A semiconductor substrate in which a valve port is formed from one surface to another surface in a thickness direction, a flexible portion having an end attached to the one surface side of the semiconductor substrate and having flexibility, and provided on the flexible portion. A valve element for opening and closing the valve port on the one surface side of the semiconductor substrate; and a first bimetal element and a second bimetal element provided on the flexible portion and made of materials having different thermal expansion coefficients. A bimetal that is laminated via an insulating layer that electrically and thermally insulates the bimetal from each other, and energizing means that energizes only one of the first bimetal element and the second bimetal element. Characteristic semiconductor microvalve.