JPH10190355A - Package for piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly precise and small crystal oscillator by providing the adjusting terminals of a piezoelectric device for a recessed part formed at the back of a package. SOLUTION: The recessed part 2 is provided at the almost central part of the back of the ceramic package for temperature compensation-type crystal oscillator, and the terminal group 3 of a temperature compensation constant adjusting terminal and a frequency adjusting terminal is formed in a grid form. A terminal group 4 as the output terminal, the power terminal and the ground terminal of the temperature compensation-type crystal oscillator is formed at the four corners of the plane part of the back of the ceramic package 1, at the base, in general. Thus, stray capacitance by wiring can considerably be reduced by forming the terminal group 3 at the back of the ceramic package 1 in the shortest distance. Then, adverse influence on the frequency owing to stray capacitance, the shift of the frequency, for example, can be avoided, and external dimension can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric device, and more particularly, to a package structure of a temperature-compensated high-precision small crystal oscillator used for a mobile communication device such as a mobile phone.

[0002]

2. Description of the Related Art Quartz oscillators are used for various types of communication equipment because of their superior frequency stability, aging, etc. as compared with oscillators using other oscillators and the like. Demand is increasing. In recent years, there has been a strong demand for miniaturization and cost reduction of temperature-compensated crystal oscillators, and in order to achieve the demand, a method of integrating an oscillation circuit, a temperature compensation circuit, and a temperature compensation constant adjustment circuit into ICs has been proposed and put into practical use. FIG. 2 shows such a temperature-compensated crystal oscillator 1
FIG. 4 is a schematic diagram in an adjustment process of 0, and is composed of a terminal group 13 for connecting the oscillator 10 and the adjustment device 12 and a terminal group 14 for connection to an output, a power supply, a ground, and the like.
The terminal group 13 is necessary only when adjusting the temperature compensation constant, output frequency accuracy, output voltage, etc. of the temperature-compensated crystal oscillator, and becomes unnecessary after the adjustment. On the other hand, the terminal group 4 is completed as a crystal oscillator. These terminals are necessary for receiving power, grounding, supplying output frequency, and the like when mounted on a mobile phone or the like.

The external output terminals of the temperature compensated crystal oscillator include the terminal group 14, a frequency output terminal 14a, a power supply terminal 14b, a ground terminal 14c (GND terminal), and several optional terminals 14d, 14e, etc. Is generally provided. On the other hand, conventionally, an oscillation circuit and a temperature compensation circuit were set, and individual compensation electronic components were determined based on the measured value of the temperature-frequency characteristic. The control can be performed by a signal, and a terminal group 13 for securing electrical conduction with the adjusting device 12 is required. The terminal group 13 includes, for example, a temperature compensation constant adjustment terminal, an output frequency adjustment terminal, an output adjustment terminal, and the like, and the number thereof is determined by the design of the IC.

FIG. 3 is a plan view showing an example of terminal arrangement on the back surface of a ceramic package 11 of a conventional temperature-compensated crystal oscillator. A terminal group 13 as a temperature compensation constant adjustment terminal, a frequency adjustment terminal, an output adjustment terminal, and the like, and a terminal group 14 as an external output terminal of the temperature-compensated crystal oscillator are arranged as soldering terminals on the back surface of the ceramic package 11. Have been. As is well known, the base portion of the ceramic package 11 for a crystal oscillator is composed of several layers.
Wiring is formed in each layer. A plurality of through conductors for connecting necessary wiring and each terminal are provided between the layers.

FIG. 4 shows an example of another ceramic package of a conventional temperature-compensated crystal oscillator. The terminal group 1 includes terminals for temperature compensation constant adjustment, frequency adjustment, and output adjustment.
FIG. 3 is a perspective view showing an example in which 3 is formed on a dummy substrate unit 15. When manufacturing the ceramic package 11, the dummy package part 15 and the dummy substrate part 15 are integrally manufactured, and the terminal group 13 is arranged on the substrate part 15. After performing necessary adjustments such as temperature compensation using the terminal group 13, the dummy substrate 15 is moved to the substrate 1.
1 along the groove BB ′ formed on the
Remove.

[0006]

However, a large number of terminals for temperature control constant adjustment, frequency adjustment, and the like are required as terminals.
In the example where 4 is arranged, the external dimensions of the ceramic package are limited by the terminal pitch and the number of terminals, and there is a disadvantage that miniaturization is difficult. In addition, the method of providing the dummy substrate portion 15 on the terminal for adjusting the temperature constant, the terminal for adjusting the frequency, and the like has a disadvantage that the substrate size is larger than the functional size that actually functions as a package, and the package cost is increased. Further, when the crystal oscillator using the above two packages is mounted on a printed board or the like, there is a disadvantage that the terminal group 14 or the wiring on the side on which the wiring is mounted may come into contact. The present invention has been made in order to solve the above-mentioned drawbacks, and has as its object to provide a high-precision and small-sized temperature-compensated crystal oscillator.

[0007]

According to a first aspect of the present invention, there is provided a surface mount type package for accommodating electronic components constituting a piezoelectric device, wherein an adjustment terminal of the piezoelectric device is provided on a back surface of the package. A package for a piezoelectric device, wherein the package is provided in a recess formed in the piezoelectric device. The invention according to claim 2 is characterized in that the shape of the recess is left-right asymmetric and the shape of the adjusting jig is made to substantially match this, thereby preventing erroneous insertion of the adjusting jig into the recess. The package for a piezoelectric device according to claim 1, wherein

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. FIGS. 1A and 1B are a plan view and a cross-sectional view taken along the line AA ′ of the back surface of a ceramic package 1 for a temperature-compensated crystal oscillator according to an embodiment of the present invention. A terminal group 3 such as a temperature compensation constant adjusting terminal and a frequency adjusting terminal is formed in a lattice shape on the portion 2. On the other hand, a terminal group 4 as an external output terminal such as an output terminal, a power supply terminal, and a ground terminal of the temperature-compensated crystal oscillator is connected to a ceramic package 1 as shown in FIG.
Are formed at the flat portion on the back surface, generally at the four corners of the bottom surface. The ceramic package 1 is composed of several layers of laminated boards, and each layer is provided with necessary wiring. Further, a conductor is formed through each layer in a hermetically sealed manner for necessary connection between layers or connection to terminals. Further, the IC 5 including the oscillation, the compensation circuit, the compensation component, and the like, and the electronic components 6, 7 and the like are mounted on the upper part of the ceramic package, and a metal cover is also put on as an electric shield and the like.

In the temperature compensation adjustment step, the probe pins are brought into contact with the temperature compensation constant adjustment terminals of the terminal group 3 formed in the recessed portions, and the information at the time of adjustment is applied to the IC 5 mounted on the ceramic package 1 via the probe pins. For example, information such as a temperature and a resistance value is written. As shown in FIG. 1 (c), an example of the probe 9 is formed so that the outer shape of the probe matches the shape of the concave portion 2, and the probe has the same number of contacts at positions corresponding to the terminal group 3. 9a is embedded and placed. The terminal dimensions of the terminal group 3 need only be large enough to allow the probe pins to come into contact with each other, and need not be soldered unlike the terminals of the terminal group 4, so that the terminal dimensions can be reduced. 2 can be provided with a large number of terminals. Accordingly, the bottom area required for the terminal group 3 can be reduced, and the size of the ceramic package 1 can be significantly reduced. A terminal group 3 such as a terminal for temperature compensation constant adjustment and a terminal for frequency adjustment is connected to the ceramic package 1.
When a large number of temperature-compensated crystal oscillators are mounted on the motherboard in the temperature compensation adjustment step, contact between the terminal groups 3 of the oscillators and the corresponding probe pins on the motherboard can be achieved. Is very easy. In addition, short-circuiting between terminals can be prevented, the degree of freedom in arrangement on the motherboard is increased, and a large number of temperature-compensated crystal oscillators can be accommodated on the motherboard.

In the conventional temperature-compensated crystal oscillator, the wiring from the temperature-compensating IC and the like to the terminal group 3 for adjustment is formed so as to cross over the surface of the ceramic package. Since a plurality of conductors penetrating the front and back of the ceramic package 1 are formed and the terminal group 3 is formed at the shortest distance on the back surface of the ceramic package 1, the stray capacitance due to wiring can be greatly reduced. For example, frequency shift can be avoided. Further, since the terminal group 3 is not formed as a plane wiring but penetrates between layers, it is also possible to increase the degree of freedom in wiring design on the ceramic package.

The recess 2 formed on the back surface of the ceramic package 1 is made asymmetrical as shown in FIG.
When contacting the terminal group 3 such as a frequency adjusting terminal, erroneous contact can be prevented. Further, since the adjustment terminal group 3 is left on the back surface of the ceramic package 1 of the temperature-compensated crystal oscillator, if the oscillation frequency or the temperature compensation changes due to aging or the like, the terminal group 3 is readjusted. It is possible.

Further, it is not always necessary to form all the adjustment terminals in one recess, and a recess may be formed for each adjustment terminal. Further, it is obvious that the present invention can be applied to a crystal oscillator that needs to expose an adjustment terminal to the outside irrespective of the temperature compensation method and the adjustment method.

When the chip component is mounted on the back surface of the ceramic substrate 1, the recess 2 for forming the terminal group 3 of the adjustment terminal and the recess for mounting the chip component are separately formed. It is possible to prevent a short circuit of the adjustment terminal due to the inflow of the conductive adhesive or solder used for joining. In the above, the case where the present invention is applied to a crystal oscillator has been described as an example. However, the present invention is not limited to this, and may be a module that requires electrical adjustment after assembly.

[0014]

Since the present invention is constructed as described above, even if there are many terminals for temperature compensation constants, terminals for frequency adjustment, etc., a remarkable effect can be obtained in reducing the external dimensions. Furthermore, when mounting on a motherboard, the wiring for adjustment only needs to be press-contacted with the contact pins, so that there is an effect that the man-hour at the time of mounting is greatly reduced.

[Brief description of the drawings]

1A is a plan view of a back surface of a package for a temperature-compensated crystal oscillator according to the present invention, FIG. 1B is a cross-sectional view of FIG.
(C) is a perspective view showing an example of a probe.

FIG. 2 is a schematic diagram showing an adjustment terminal and an output terminal of the temperature compensated crystal oscillator.

FIG. 3 is a plan view showing a back surface of an example of a conventional ceramic package for a temperature-compensated crystal oscillator.

FIG. 4 is a perspective view showing the back surface of another conventional ceramic package for a temperature-compensated crystal oscillator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic package 2 ... Depressed part 3 ... Terminal group for temperature compensation constant adjustment, frequency adjustment, etc. 4 ... External terminal group for output, power supply, grounding, etc. 5 ... IC 6, 7: Electronic component 8: Lid 9: Probe 9a: Contact A, A ': Cutting point

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H03H 9/10 H03H 9/10

Claims (2)

[Claims] 1. A package for a piezoelectric device, wherein an adjustment terminal of the piezoelectric device is disposed in a concave portion formed on a back surface of the package in a surface mounting type package for housing electronic components constituting the piezoelectric device. 2. The erroneous insertion of the adjusting jig into the concave portion is prevented by making the shape of the concave portion left-right asymmetric and making the shape of the adjusting jig substantially coincide with the shape of the adjusting jig. Item 7. A package for a piezoelectric device according to Item 1.