JP2000323927A - Piezoelectric oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small-sized piezoelectric oscillator which is low-priced by simplifying the manufacture process and improving the production efficiency by constituting an amplifying circuit in an IC and connecting the amplifying circuit and a capacitive element to a ceramic container by a flip chip method. SOLUTION: A crystal oscillator 1 is equipped with an oscillator circuit 3 including electronic circuits such as an amplifying circuit for amplifying a signal of a crystal vibrator 2 and a temperature compensating circuit, a capacitive element 4 for DC cutting which extracts an AC component from the output signal of the oscillator circuit 3, a ceramic container 5 which has a recessed part for storing them, and a lid 6 which seals an opening part of the ceramic container 5. Then the oscillator circuit 3 is constituted in an IC and mounted in the recessed part of the ceramic container 5 by the flip chip method. Similarly, the capacitive element 4 is mounted in the recessed part of the ceramic container 5 by using the flip chip method. Consequently, the capacitive element 4 can be mounted in the same process with the oscillator circuit 3, so the cost can greatly be lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric oscillator,
In particular, it relates to a small piezoelectric oscillator.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of communication equipment, it has been required that a reference signal source used for the communication apparatus be small. For example, a crystal oscillator having a structure as shown in FIG. 5 has been proposed. . FIG. 1A is a circuit diagram of a conventional crystal oscillator.
FIG. 1B is a side cross-sectional configuration diagram when the crystal oscillator is assembled.

[0003] As shown in FIG.
Is an oscillator circuit 102 including an electronic circuit such as a crystal oscillator 101, an amplifier circuit for amplifying a signal of the crystal oscillator 101 and a temperature compensation circuit, and a direct current (DC) extracting an AC component from an output signal of the oscillator circuit 102. And a capacitive element 103 for cutting. Furthermore, such a crystal oscillator 1
00 denotes the oscillator circuit 10 as shown in FIG.
2 is formed into an IC, and is mounted, for example, in a recessed portion of the ceramic container 104 by using a flip chip method, thereby realizing the miniaturization by reducing the storage space of the ceramic container 104.

[0004] Further, there is an idea that the DC cut capacitive element is made into a semiconductor and made into an IC together with the oscillator circuit 102 to realize miniaturization. DC current leaks to the oscillator output OUT via an electrostatic protection circuit or the like which is indispensable for compensating for the problem, and does not function sufficiently as a DC cut capacitor. Therefore, at present, the capacitor 103 is not integrated with the oscillator circuit 102 but uses a chip-type ceramic capacitor.
Therefore, in the crystal oscillator 100, after mounting the oscillator circuit 102, the chip type ceramic capacitor 103 is mounted in the ceramic container 104 by using the reflow method.
After that, to mount the crystal unit 101 horizontally,
With one end (free end) supported by a pillow portion 105 provided in the ceramic container 104, a conductive adhesive 106 is applied so as to connect the other end to a predetermined portion of the ceramic container 104. .

[0005] The free end of the quartz oscillator 101 is lifted up from the pillow portion 105 due to the shrinkage force of the conductive adhesive 106 when it is hardened, thereby holding the quartz oscillator 101 at one end. This is completed through a step of sealing the opening of the opening 104 with the lid 107.

[0006]

However, in the above configuration, the oscillator circuit 102 and the capacitor 103
Because the method of mounting in the ceramic container 104 differs between
There has been a problem that the manufacturing process is complicated and the price of the crystal oscillator cannot be sufficiently reduced. That is, while the oscillator circuit 102 made into an IC is connected by using an ultrasonic wave such as a flip chip method or a wire bonding method, a chip type ceramic capacitor 103 is used.
Is based on the premise of solder connection, and the mounting method by the reflow process must be used. As is well known, a chip capacitor is premised on solder connection, so that its electrodes are generally plated in advance with solder. Therefore, even if the terminal connection is attempted by the flip chip method, the solder plating is melted by the heat applied when mounting the crystal oscillator, and the fixing strength necessary for maintaining the connection is lost, Mounting methods other than the solder connection such as the flip chip method were impossible.

Therefore, in order to assemble the crystal oscillator 100, it is necessary to prepare separate mounting systems for the crystal oscillator circuit 102 and the capacitive element 103, thereby increasing the capital investment and further increasing the work time. This necessitates the steps described above, which complicates the manufacturing process, and as a result, there has been a problem that the cost of the crystal oscillator cannot be reduced. The present invention has been made in order to solve various problems of the conventional piezoelectric oscillator, and has as its object to provide a small-sized piezoelectric oscillator that simplifies a manufacturing process, improves production efficiency, and is inexpensive.

[0008]

According to a first aspect of the present invention, there is provided a piezoelectric vibrator comprising: a piezoelectric vibrator;
An amplifier circuit for amplifying a signal of the piezoelectric vibrator, a DC cut capacitance element for extracting an AC component of an output signal of the amplifier circuit, and a ceramic container including a ceramic container for accommodating the same. The amplifier circuit is an integrated circuit, and the amplifier circuit and the capacitor are connected to the ceramic container by a flip-chip method.

According to a second aspect of the present invention, there is provided a piezoelectric vibrator, an amplifying circuit for amplifying a signal of the piezoelectric vibrator, a DC cut capacitor for extracting an AC component of an output signal of the amplifying circuit, In a piezoelectric oscillator provided with a ceramic container for accommodating these components, the amplifier circuit is formed into an IC, and the amplifier circuit and the capacitor are connected to the ceramic container using the same manufacturing process. It is characterized by:

According to a third aspect of the present invention, in addition to the first and second aspects, the piezoelectric vibrator is held at one end in the ceramic container, and the vicinity of a free end of the piezoelectric vibrator and the ceramic container are connected to each other. Characterized in that the capacitive element is disposed between them.

According to a fourth aspect of the present invention, in addition to the first to third aspects, the capacitive element is a semiconductor capacitive element.

According to a fifth aspect of the present invention, in addition to the fourth aspect, the semiconductor capacitance element is a variable capacitance diode.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 is a sectional view showing the configuration of an embodiment of a crystal oscillator according to the present invention. As shown in FIG. 1, a crystal oscillator 1 includes a crystal oscillator 2, an oscillator circuit 3 including an electronic circuit such as an amplifier circuit for amplifying a signal of the crystal oscillator 2 and a temperature compensation circuit, and an oscillator circuit 3. A capacitive element 4 for cutting off a direct current component from the output signal, a ceramic container 5 having a recess for accommodating them, and a lid 6 for sealing the opening of the ceramic container 5. I have.

One of the features of the present invention is the use of a capacitive element 4 whose electrode surface is not solder-plated as the capacitive element 4. For example, the electrode portion is made of silver palladium,
It is made of metal such as gold or aluminum. In such a ceramic capacitor, for example, as the capacitive element 4, a chip component before solder plating by a capacitor maker or a specially manufactured one is used. On the other hand, a semiconductor capacitor element or a variable capacitance diode element, which is made of the above-described metal material without solder plating on the electrode portion, is commercially available, and can be obtained at relatively low cost. Is more economical.

FIG. 2 is a circuit diagram showing an example of the crystal oscillator 1 when a variable capacitance diode is used as the DC cut capacitance element 4. As shown in the figure, the oscillator circuit 3 is connected to the variable capacitance diode without applying a DC bias.
Is inserted between the oscillator output OUT and the oscillator output OUT, there is some variation in the capacitance value due to the current based on the oscillator output signal. No problem. At this time, when the oscillation frequency is, for example, 10 MHz or more, it is sufficient that the capacitance value of the variable capacitance diode is 100 pF or more.

In the crystal oscillator 1 as described above, the oscillator circuit 3 is formed into an IC as in the prior art, and is mounted in the recess of the ceramic container 5 by, for example, a flip chip method. However, a major feature is that the capacitive element 4 is mounted in the recess of the ceramic container 5 using the same flip chip method.
Thereby, the capacitive element 4 is formed in the same process as the oscillator circuit 3.
Can greatly reduce the cost.

FIG. 3 is a sectional view showing another embodiment of the crystal oscillator according to the present invention. The feature of the crystal oscillator 1 shown in the figure is that the capacitive element 4 mounted in the package by the flip chip method is used as the pillow portion 7 when the crystal resonator 2 is mounted.

In this case, it is desirable to use the capacitor 4 having a structure as shown in FIG.
FIG. 4 is a perspective view showing the configuration of the capacitive element 4. The functional element 9 is provided on a surface connected to the ceramic container 5, and a ground is formed on the entire surface facing the functional terminal 9.
No terminal is provided. This is the capacitance element 4
When the functional terminal 9 is present in the vicinity of the crystal unit 2, the oscillation signals are mutually coupled, or when the crystal unit 2 is bent by an impact applied to the oscillator, the functional terminal 9 is electrically contacted. This is to prevent that. In the above description, the present invention has been described using the flip chip method. However, the present invention is not limited to this, and another semiconductor component mounting method such as a wire bonding method may be used.

Although the present invention has been described with reference to an oscillator using a crystal element as an example, the present invention is not limited to this, and is applicable to an oscillator using a piezoelectric vibrator other than crystal. Obviously it is good.

[0020]

As described above, the piezoelectric oscillator according to the present invention comprises a piezoelectric vibrator, an amplifying circuit for amplifying a signal of the piezoelectric vibrator, and a DC for extracting an AC component of an output signal of the amplifying circuit. In a piezoelectric oscillator including a capacitive element for cutting and a ceramic container for accommodating the same, the amplifying circuit is formed into an IC, and the amplifying circuit and the ceramic container, and the capacitive element and the ceramic By connecting the container and the container by the same manufacturing process, there is an effect that the manufacturing process is simplified and a sufficient price reduction is achieved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an embodiment of a crystal oscillator according to the present invention.

FIG. 2 shows a circuit diagram of another embodiment of the crystal oscillator according to the present invention.

FIG. 3 is a sectional view showing another embodiment of the crystal oscillator according to the present invention.

FIG. 4 is a perspective view of a DC cut capacitor used in the crystal oscillator according to the present invention.

FIG. 5 shows a configuration diagram of a conventional crystal oscillator. (A) is a circuit diagram of a conventional crystal oscillator. FIG. 2B is a side cross-sectional configuration diagram of a conventional crystal oscillator.

[Explanation of symbols]

1,100 crystal oscillator, 2,101 crystal oscillator, 3,1
02 oscillator circuit, 4, 103 capacitance element, 5, 104 ceramic container, 6, 107 lid, 7, 105 pillow, 8, 10
6 conductive adhesive, 9 functional terminals

Claims (5)

[Claims] 1. A piezoelectric vibrator, an amplifying circuit for amplifying a signal of the piezoelectric vibrator, a DC cut capacitor for extracting an AC component of an output signal of the amplifying circuit, and a ceramic container for accommodating these components Wherein the amplifying circuit is integrated into an IC, and the amplifying circuit and the capacitive element are connected to the ceramic container by a flip-chip method. 2. A piezoelectric vibrator, an amplifying circuit for amplifying a signal of the piezoelectric vibrator, a DC cut capacitor for extracting an AC component of an output signal of the amplifying circuit, and a ceramic container for accommodating the same. Wherein the amplifying circuit is integrated into an IC, and the amplifying circuit and the capacitive element are connected to the ceramic container using the same manufacturing process. Oscillator. 3. The piezoelectric vibrator according to claim 1, wherein the piezoelectric vibrator is held at one end in the ceramic container, and the capacitance element is arranged between a vicinity of a free end of the piezoelectric vibrator and the ceramic container. The piezoelectric oscillator according to claim 2. 4. The piezoelectric oscillator according to claim 1, wherein said capacitance element is a semiconductor capacitance element. 5. The piezoelectric oscillator according to claim 4, wherein said semiconductor capacitance element is a variable capacitance diode.