JPH0735451Y2 - Piezoelectric device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a field of application of a piezoelectric device, and more particularly to a piezoelectric device in which a circuit element is mounted in a container for sealing a crystal blank.

(Background of the Invention) Since a crystal resonator has excellent resonance characteristics, it is often used as an oscillator, a filter element, or the like in communication equipment, for example. In recent years, due to the trend toward miniaturization of various electronic devices, there is an increasing demand for a piezoelectric device in which a circuit element and a crystal oscillator are enclosed in a single container, for example, a small piezoelectric oscillator.

(Prior Art) FIG. 6 is a sectional view of a small piezoelectric oscillator for explaining a conventional example.

The small piezoelectric oscillator is a substrate 1 on which a conductive path (not shown) is formed.
The crystal piece 2 and the circuit element 3 (capacitor, resistor, IC, etc.) are mounted on (for example, ceramics). The substrate 1 is laid on the metal base 4 from which the terminals are led out. Electrodes (not shown) are formed on both main surfaces of the crystal piece 2, and the outer peripheral portions of both ends of the electrode, which are extended, are connected to the holder 5. Then, the cover 6 is sealed on the outer periphery of the metal base 4 by, for example, resistance welding.

(Problems of Prior Art) However, in such a structure, the crystal element 2 is enclosed in the same container as the circuit element 3. Therefore, the circuit element 3
However, there is a problem in that the generation of gas due to the secular change adversely affects the crystal blank 2 and deteriorates its characteristics such as the change of the oscillation frequency.

For this reason, for example, it is considered that the crystal piece 2 is hermetically sealed in a metal container and mounted on the substrate 1. However, in this case, the crystal blank 2 is double-sealed, and there is a problem that the utilization efficiency of the container is poor and it is not suitable for downsizing.

(Object of the Invention) An object of the present invention is to provide a piezoelectric device suitable for miniaturization while maintaining the characteristics of the piezoelectric vibrator.

(Solution) According to the present invention, a first conductive path connecting to an electrode of a piezoelectric piece is provided on a substrate 1.
And a second conductive path connecting to the first conductive path is formed on the outer surface of the cover, and a recess is provided on the outer surface of the cover, and a circuit element is embedded in the recess. To do. An embodiment of the present invention will be described below.

(Embodiment) FIG. 1 is an exploded view of a piezoelectric device for explaining an embodiment of the present invention. It should be noted that the same parts as those of the previous conventional example are given the same numbers to simplify the description.

In the small piezoelectric device, a quartz piece 2 is mounted on a substrate 1 made of ceramics. A conductive holder 5 is fixed on the substrate 1,
The outer peripheral portions of both ends of the electrode 7 of the crystal piece 2 are electrically and mechanically connected and held. In addition, a first conductive path 8 connected to the holder 5 and extending to the end is formed on the substrate 1. The cover 9 is made of ceramics like the substrate 1, and two recesses 10 are formed on the main surface of the outer surface. Then, a capacitor 11 is embedded in the recess as a part of the piezoelectric oscillator shown in FIG. Further, the second conductive paths 12 extending from the both ends of each recess 10 to the side end are formed. Then, each second conductive path and the electrode portion of each capacitor 11 are bonded by a conductive adhesive or the like. The conductive paths on one end side of each recess 10 are commonly connected to form a third conductive path 13. Then, the upper surface of the side wall of the cover 9 is fixed to the outer peripheral surface of the substrate 1 by, for example, the low-melting glass 14 and sealed. Next, the first conductive path 8 of the substrate 1 and the second conductive path 12 of the cover are connected by a not-illustrated conductive adhesive, for example.

In such a structure, since the crystal piece 2 is hermetically sealed in the container, it is not affected by the environmental influence of other circuit elements, and the characteristic as the crystal resonator is maintained well. Since the circuit element is embedded in the recess 10 provided on the outer surface of the container, its positioning is facilitated.

(Other Matters) In the above embodiment, the recess 10 is provided on the main surface of the cover 9 to bury the capacitor, but the recess 10 may be provided on one side as shown in FIG. 3, for example. . In this case, the main surface is made of a ceramic surface having no recess and no conductive path, which facilitates printing and display.

Further, although the capacitor is buried in the recess 10, a part or all of the oscillator circuit (see FIG. 2) is formed by expanding the recess (however, the crystal piece is sealed in the container). You may. In this case, for example, as shown in FIG. 4, an IC chip may be fixed to the recess and connected to a conductive path (not shown) by bonding. Also, the fifth
As shown in the cross-sectional view of the drawing, a cover in which some of the elements are embedded on the substrate 1 may be sealed, and the remaining elements may be mounted on the blank portions of the substrate.

(Effect of the Invention) According to the present invention, a first conductive path that is connected to an electrode of a piezoelectric piece is provided on a substrate, a second conductive path that is connected to the first conductive path is formed on an outer display of the cover, and Since the external display is provided with a recess and the circuit element is embedded in the recess, it is possible to provide a piezoelectric device suitable for miniaturization while maintaining the characteristics of the piezoelectric vibrator.

[Brief description of drawings]

FIG. 1 is an exploded view of a piezoelectric device for explaining an embodiment of the present invention, and FIG. 2 is a circuit diagram of a piezoelectric oscillator. FIG. 3 is a perspective view of a piezoelectric device illustrating another embodiment of the present invention, and FIG. 4 is a partial sectional view illustrating yet another embodiment.
FIG. 5 is a sectional view for explaining still another embodiment. FIG. 6 is a sectional view of a piezoelectric oscillator for explaining a conventional example.

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric device in which a piezoelectric piece is mounted on a substrate and sealed with a cover, the piezoelectric device being formed on the substrate, connected to each electrode of the piezoelectric piece, and extending in opposite directions to an end of the substrate. A first conductive path, a recess formed on the outer surface of the cover, a circuit element embedded in the recess, and one end formed on the outer surface of the cover connected to the first conductive path and the other end And a second conductive path connected to one end of the circuit element.