JPH0374042B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting an oscillator used in a watch or the like.

Conventionally, a trimmer capacitor is placed in a recess in the base of a sealed container that encloses an integrated circuit element including a piezoelectric resonator such as a crystal resonator, its oscillation circuit, frequency dividing circuit, etc., and the trimmer capacitor is adjusted. There is an oscillator that adjusts the oscillation frequency. Since the trimmer capacitor of this oscillator is exposed to the outside of the sealed container, the oscillation frequency fluctuates due to the influence of humidity, etc., and oscillation stops when water droplets adhere to the oscillator. In order to solve these drawbacks, in the prior art, the capacitance of the trimmer capacitor is adjusted and then the trimmer capacitor is molded. However, according to this method, after the trimmer capacitor is adjusted, molding material flows between each high-frequency lead, so capacitance is formed between each high-frequency lead due to the dielectric effect of this molding material, and as a result, The capacitance of the entire oscillation circuit deviates from the value when adjusting the trimmer capacitor. As a result, the oscillation frequency fluctuates, making it unsuitable for high-precision clocks and the like.

The present invention eliminates the above-mentioned drawbacks, and embodiments thereof will be described below with reference to the drawings.

In FIGS. 1 and 2, a sealed container 1 consists of a base 3 having a plurality of leads hermetically fixed to it using an airtight glass 2, and a cap 4 hermetically fixed to the base. The base 3 has a recess 3a that opens outward around the plurality of leads. One end of the leads 5 and 6 inside the sealed container 1 protrudes from the other leads, and the other end outside the sealed container 1 is short and located within the recess 3a. Holding springs 7 and 8 are conductively fixed to one ends of the leads 5 and 6 as high-frequency leads using a conductive adhesive, and a crystal resonator 9, which is a piezoelectric vibrator, is similarly conductively fixed to these holding springs. There is. For this purpose, drive electrodes 9 are formed on both sides of the crystal resonator 9 by vacuum deposition or the like.
A and 9b are electrically connected to leads 5 and 6, respectively. 10 is the X _T lead, 11 is the X _T lead,
One end protrudes low inside the sealed container 1, and the other end outside the sealed container 1 is located in the recess 3a. Leads 5 and 6, _T lead 10, X _T lead 11, 4
A high-frequency current flows through the lead of a book, making it a high-frequency lead. 12 and 13 are output leads, 14 is a V _DD lead, and 15 is a V _SS lead.
One end of these four leads inside the sealed container 1 projects low, and the other end outside the sealed container 1 is long and projects beyond the recess 3a. Other leads are not used in this embodiment. Reference numeral 16 denotes an integrated circuit element, which is die-bonded on the upper surface of the base 3. The integrated circuit element 16 includes an oscillation circuit that causes the crystal resonator 9 to oscillate, a frequency dividing circuit that divides the frequency of the signal, and the like. The integrated circuit element 16 may include an alarm sound generating circuit or the like, in which case the previously described unused leads are used. 17 is a wiring board including a trimmer capacitor, which is located in the recess 3 of the base 3.
It is supported by a lead within a and fixed with a conductive adhesive or the like. The wiring board 17 is sealed in the recess 3a with a molding material M.

The wiring board 17 will now be described in detail with reference to FIGS. 3 and 4.

The wiring board 17 is made by first forming conductor layers 18 and 19 on a substrate made of ceramic or the like, forming a dielectric layer 20 on top of the conductor layers 18 and 19, and then forming a conductor layer 2 on top of the dielectric layer 20.
1 was formed. A notch 17 is provided on the outer periphery of the wiring board 17 to avoid each lead of the airtight terminal 3.
a, 17b...17i and a through hole 17j are formed, and the leads 5, 6 are formed with notches 17f, 17i, respectively.
Compatible with 17a, _T lead 10, X _T lead 11
correspond to the notches 17c, 17b, respectively, and the output leads 12, 13 correspond to the notches 17g, 17, respectively.
h, the V _DD lead 14 and the V _SS lead 15 correspond to the through hole 17j and the notch 17e, respectively. The conductor layer 18 connects the notch 17c and the notch 17f, and connects the lead 5 and _{the T} -lead 10. In addition, the conductor layer 18 and the upper conductor layer 2
A dielectric layer 20 is sandwiched between the capacitor 1 and the capacitor 2.
2 is formed. The conductor layer 19 has a notch 17a
and the notch 17b, thereby connecting the lead 6 and the _XT lead 11. Also, the conductor layer 19
A trimmer capacitor 23 is formed by sandwiching a dielectric layer 20 between the upper conductor layer 21 and the upper conductor layer 21 . This trimmer capacitor reduces the capacitance by removing the upper conductor layer 21 using a sandplast device, a laser device, or the like. The substrate of the wiring board 17 is made of alumina porcelain, steatite porcelain, or the like. The conductor layers 18, 19 and the upper conductor layer 21 are formed by printing a conductor paste such as silver, silver palladium, or tungsten, and the dielectric layer 20 is formed by printing a dielectric paste such as glass or alumina. It was formed. Then, these are fired in a laminated state to form the wiring board 17 including the trimmer capacitor 23.

Next, with reference to FIG. 5, the wiring of the oscillator of the present invention will be explained.

24 is a feedback resistor, 25 is an inverter, and these are included in the integrated circuit element 16.
The capacitor 22 and trimmer capacitor 23 are the same as those shown in the third figure. One lead 6 of the crystal resonator 9 is connected to the X _T lead 11 on the input side of the inverter 25 through a conductor layer 19.
A trimmer capacitor 23 shown in the third and fourth figures is formed between the upper conductor layer 21 and the upper conductor layer 21 . Further, the other lead 5 of the crystal resonator 9 is connected to _{the T} lead 10 on the output side of the inverter 25 through a conductive layer 18.
A capacitor 22 shown in the third and fourth figures is formed between this conductor layer 18 and the upper conductor layer 21.

Here, the above-mentioned molding material M will be explained in detail.

The molding material M is made up of a first molding material M1 and a second molding material M2. The first molding material M1 includes the gap between the bottom surface of the airtight glass 2 and the wiring board 17, at least the leads 5 and 6 which are high frequency leads, _{the T} lead 10, as shown in the first and seventh figures.
It covers the _XT lead 11 and the conductor layer connected thereto, leaving the upper conductor layer 21 exposed. Therefore, the trimmer capacitor 2 is removed by removing the conductor layer 21 using a sandblasting device or the like.
3 adjustments are possible. And second mold material M
2 covers all exposed parts of the wiring board 17 and completely encapsulates the wiring board 17.

Next, a method for adjusting the oscillator according to the present invention will be described with reference to FIGS. 6 to 8.

As shown in FIG. 6, a wiring board 17 is positioned in the recess 3a of the base 3 of the sealed container 1, and is supported and fixed to each lead.

First, a first molding material M1 is injected into the recess 3a to cover the high frequency leads as shown in FIG. In this state, the oscillator is caused to oscillate, the conductor layer 21 is removed by a sandblasting device, and the capacitance of the trimmer capacitor 23 is adjusted to set a desired oscillation frequency.
After this alignment is completed, the exposed portion of the wiring board 17 is completely molded with the second molding material M2 as shown in FIG. 8, and the trimmer capacitor 23 is encapsulated. In this manner, the oscillation frequency is prevented from fluctuating due to the dielectric effect of the molding material because the high-frequency lead is first molded with the first molding material and then the trimmer capacitor is adjusted to match the oscillation frequency. Furthermore, since the trimmer capacitor is then completely molded, the oscillation frequency will not fluctuate due to the influence of humidity, and oscillation will not stop even if water droplets adhere to it.

FIG. 9 shows another embodiment of the present invention, in which a conductive layer 26 for shielding is attached to the surface of the molding material M. This conductive layer is made by applying conductive paste or the like with a brush or the like so as not to come into contact with the protruding leads, and is connected to the base 3 and has the same potential as the sealed container 1. The conductor film 26 is not limited to brush painting, but may be formed by shielding the lead portion with a mask and forming a metal film by sputtering or the like. By providing a conductive film in this way, it will not be affected by stray capacitance,
It becomes a more stable oscillator.

In this embodiment, the trimmer capacitor 23 is adjusted, but the capacitor 22 may also be adjusted.

Further, although the trimmer capacitor is shown as having no conductor film, it may be of a normal rotating electrode type.

As described above, according to the present invention, first the space between the multilayer capacitor and the airtight glass and the high frequency lead are molded, then the electrode portion is trimmed to adjust the capacitance of the multilayer capacitor, and then the multilayer capacitor Since it is molded so that it is buried, the oscillation frequency can be matched with extremely high precision without being affected by the electrostatic coupling between the high frequency leads caused by the mold. Furthermore, since the molding material is injected into the recess, it is difficult to peel off, and the molding effect lasts for a long period of time. It is completely unaffected by humidity and can oscillate even if water droplets adhere to it.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a bottom view thereof, FIG. 3 is an enlarged front view of a wiring board including a trimmer capacitor, FIG. FIG. 5 is an electric circuit diagram, FIGS. 6 to 8 are explanatory diagrams showing an adjustment method, and FIG. 9 is a bottom view showing another embodiment. 1... sealed container, 2... airtight glass, 3... base, 3a... recess, 4... cap, 5, 6,
10, 11... High frequency lead, 16... Integrated circuit element, 17... Wiring board, 23... Trimmer capacitor, 26... Conductor film, M... Mold material, M1
...First mold material, M2...Second mold material.

Claims (1)

[Claims] 1. A piezoelectric vibrator and its oscillation circuit are contained in a sealed container consisting of a base on which a plurality of leads are implanted through airtight glass and a metal cap sealed to the base. The integrated circuit is sealed, and a downwardly opened recess formed by the lower surface of the airtight glass and the lower side wall of the base is formed in the lower part of the sealed container, and the recess is formed in the lower part of the sealed container. In the above, a multilayer capacitor is connected and supported with a gap between the airtight glass and the high frequency lead which is connected to the piezoelectric vibrator among the leads with its electrode portion facing the opening. In the oscillator adjustment method in which the high-frequency lead is formed so that its tip is located within the recess, first, the space between the multilayer capacitor and the airtight glass and the high-frequency lead are molded, and then the electrode is molded. A method for adjusting an oscillator, comprising: adjusting the capacitance of the multilayer capacitor by trimming the multilayer capacitor; and then molding the multilayer capacitor so that it is buried therein.