JPS5923485B2 - Piezoelectric element holding device and its assembly method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric element holding device and a method for assembling the same.

A conventional piezoelectric element holding device is one in which a holding spring is fixed to a terminal pin implanted on a base by electric welding, etc., and the false side of the piezoelectric element is held by this holding spring via a conductive adhesive. Met.

However, since the outer side of the piezoelectric element is held by a holding spring, it cannot be held firmly and has the disadvantage that it is not necessarily strong against external forces.

The present invention aims to eliminate the above-mentioned drawbacks, and one embodiment thereof will be described below with reference to the drawings.

As shown in FIG. 1, the base 1 filled with glass has
A plurality of terminal pins 2a, 2b, 2c are inserted through the terminal,
At the upper end of each terminal pin located on the base, a substrate, for example a circuit board 3, is held vertically.

On one side of the circuit board 3 are circuit patterns 4a, 4b, 4c.
, 4d, 4e, and 4f are formed, among which the circuit pattern 4b.

4c and 4d are electrically connected to the terminal pins 2a, 2b, and 2c, and both ends of the circuit pattern 4a are connected to the ground terminal 5.
It is grounded to the base 1 through a and 5a.

Further, an integrated circuit (IC chip) 6 is die-bonded to the circuit board 3, and each circuit element of this IC chip and each pattern 4a to 4f are electrically connected by bonding wires.

By the way, approximately in the center of the circuit board 3, a circular through hole γ is bored as shown in Figure 1. There is enough to store it.

As shown in FIGS. 2 and 3, the crystal oscillator 9 is fixedly housed in the through hole γ by a plurality of holding plates 10, 11, and 12 that are fixed to the outer periphery of the through hole on the back surface of the circuit board 3. Retained.

Here, the holding plates 10, 11, 12 and the state in which the crystal resonator 9 is held by the holding plates will be explained.

The holding plates 10, 11.12 have through holes T as shown in FIG.
It has a shape that follows the rows of , that is, it has an arc shape that is the same as the inner diameter of this through hole, and the adjacent parts of each holding plate are spaced at a constant interval 13 to prevent short circuits.

Before assembly, the holding plates 10, 11, 12 are connected by connecting pieces 14, 14, 14, as shown in Fig. 4, but they are cut off from the cutting line during assembly. be.

Each holding plate 10, 11, 12 is provided with projecting pieces 10a, 11a, and 12a integrally projecting toward the center of the through hole 1, respectively.

As shown in FIG. 2, each protrusion 10a, lla, 12
In a, the back surface of the crystal resonator 9 is supported at three points via a conductive adhesive 15.

In addition, a load capacitor (capacitor) 1 is provided on both sides of the crystal resonator 9.
6.17 is formed by vapor deposition.

That is, as shown in FIGS. 5A to 50 and FIG. 2, base electrode films 19 and 20 and respective extraction electrodes 19a and 20a are first deposited on both sides of the crystal piece 18.

The upper surface of each base electrode film 19, 20 is covered with a dielectric film 21 (the dielectric film on the back side is not shown).

) is deposited on the upper surface of the dielectric film 21, and a ground electrode film 22 is further formed on the upper surface of the dielectric film 21 without shorting with the base electrode film 19, 20.
．． 23 and its extraction electrodes 22a and 23a are vapor deposited.

The extraction electrodes 22a and 23a are connected to the circuit pattern 4a.
, 20a is pattern 4e, and 19a is pattern 4.
f and the conductive adhesive 15a (through which they are electrically conductive).

Note that 24 is a frequency fine adjustment film.

Next, a method for manufacturing the holding device will be explained.

The above-described through hole 1 is bored in the circuit board 3.

Further, as shown in FIG. 4, the holding plates 10, 11, 12 are ring-shaped pieces connected by connecting pieces 14, 14, 14, and are integrally formed using a press machine or the like.

Projections 10a, 11a of each retainer plate 10, 11.12.

12a is an extraction electrode 23a of the crystal resonator 9.

19a and 20a are made to correspond to each other, and their back surfaces are adhesively fixed with a conductive adhesive 15.

In the state shown in the fourth figure, each connecting piece 14, 14.
Cut 14 from the cutting line.

Next, as shown in FIG. 2, a holding plate 10° 11.12 is set on the back side of the circuit board 3 and around the through hole γ, and
After positioning the crystal resonator 9 in this through hole, the holding plate i
o, i1°12 are fixed on the circuit board.

After that, as shown in FIG.
2a.

23a, 20a, and 19a are connected to a circuit pattern 4a, 20a, and 19a using a conductive adhesive 15a.
Make this conductive.

Note that in the crystal resonator 9, an example has been shown in which the dielectric film 21 is interposed between the base electrode film 19.20 and the earth electrode film 22.23 to configure a load capacitance of 16.1γ. The load capacitance does not necessarily need to be formed on both sides, and may be formed on one side.

The crystal resonator 9 is not limited to three-point support as shown above, but if the crystal resonator does not have a heat load capacity, two-point support using a holding plate is sufficient.

Further, the material of the circuit board 3 is selected appropriately; for example, if ceramic is used, which has almost the same coefficient of expansion as the crystal blank 18, the adverse effects of temperature changes on the holding of the crystal resonator 9 will be avoided. It becomes less.

As explained above, according to the present invention, since one side of the piezoelectric element is supported by the holding plate of the piezoelectric element, it is stable against opening force.

Since the piezoelectric element is housed in the through hole of the substrate, the overall shape can be made thin.

Furthermore, manufacturing and assembly work can be easily performed. Furthermore, if the substrate is made of ceramic, the holding state of the piezoelectric element will be more stable, and the effect will be great.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is a front view, Fig. 2 is a back view of the circuit board, Fig. 3 is a sectional view taken along the line ■-■ in Fig. 2, and Fig. 4 is a crystal vibration diagram. 5A to 50 are front views showing the state before assembly of the child holding plate, and are explanatory diagrams showing the order of forming the crystal resonator. 1...Base, 3...Circuit board, γ・
...Through hole, 8...Gap, 9...
Crystal oscillator, io, il. 12... Holding plate, 14... Connecting piece, L
...... Cutting line.

Claims (1)

[Scope of Claims] 1. A substrate in which a piezoelectric element is housed with a certain gap and a through hole of a size sufficient for the temple is bored, and a substrate is fixed to the substrate for opening the through hole and opening the piezoelectric element. 1. A holding device for a piezoelectric element, comprising a plurality of holding plates for supporting a piezoelectric element. 2. A piezoelectric element holding device according to claim 1, characterized in that the substrate is made of ceramic. 3. The piezoelectric elements can be housed on the substrate with a certain gap between them (after making sufficient through holes and fixing a plurality of holding plates connected in advance by connecting pieces to the outer periphery of the piezoelectric element or the substrate, A method for assembling a piezoelectric element holding device, comprising cutting off each of the connecting pieces and fixing each holding plate to the outer periphery of the through hole of the substrate.