JP4127445B2 - Surface mount package - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric device, and more particularly to a package structure of a temperature compensated piezoelectric oscillator used in a mobile communication device such as a mobile phone.
[0002]
[Prior art]
In general oscillators, a printed circuit pattern for an oscillation circuit is arranged on a multilayer substrate and hermetically sealed in the same atmosphere as electronic components such as capacitors, resistors, and integrated circuits that compose the oscillation circuit on the same plane of the multilayer substrate. An oscillator was configured by mounting the piezoelectric vibrator.
[0003]
[Problems to be solved by the invention]
The piezoelectric vibrator constituting the oscillator has a temperature characteristic in which the frequency changes depending on the environmental temperature. As an example, in an AT-cut plate crystal unit, the temperature with the smallest center frequency variation is set to around 25 ° C, and the frequency variation increases on the high and low temperature sides. It is known to have characteristics.
[0004]
As a recent trend, miniaturization, weight reduction, and price reduction are rapidly developing mainly in the mobile communication field such as wireless communication devices and mobile phones. Therefore, in order to reduce the size and cost of a temperature compensated oscillator that meets these requirements, a structure in which electronic components and a hermetically sealed piezoelectric vibrator are mounted on the same plane of the multilayer substrate is used. Therefore, a mounting area corresponding to the hermetic container structure of the piezoelectric vibrator is required, and there are restrictions on downsizing. In addition, if the piezoelectric vibrator is exposed from the hermetically sealed piezoelectric vibrator and is made into an airtight container structure in the same atmosphere, the temperature compensated oscillator is a temperature compensated oscillator, especially in the case of a temperature compensated piezoelectric oscillator. In the present situation, it is difficult to maintain the temperature compensation characteristic because the ambient temperature of the piezoelectric vibrator changes due to the heat generated by the electronic components that constitute the structure.
[0005]
On the other hand, regarding the realization of lower prices, the cost of electronic parts is higher than the cost of piezoelectric vibrators for the piezoelectric vibrators and electronic parts that make up a temperature compensated oscillator. Since it is often caused by various characteristics of the vibrator, it may be necessary to satisfy the desired characteristics of the piezoelectric vibrator before assembly and to suppress the consumption of electronic components.
[0006]
[Means for Solving the Problems]
In order to solve these problems, in the present invention, a surface in which the piezoelectric vibrator is arranged at the bottom of a concave portion of a concave surface-mount package that houses the piezoelectric vibrator and electronic components, and a blocking plate is arranged above the piezoelectric vibrator. In the mountable package, the blocking plate seals a part of the concave portion in which the piezoelectric vibrator is housed, and the electronic component is mounted on a lid portion of the package. The electronic component and the piezoelectric vibrator Is a surface mount package that is electrically connected and constitutes a piezoelectric oscillator that covers the lid so that the electronic component is positioned above the piezoelectric vibrator.
[0007]
In this case, the oscillation circuit is mounted on the inner surface of the lid having a sealed structure of the piezoelectric vibrator, and the piezoelectric vibrator and the oscillation circuit are divided by the lid of the piezoelectric vibrator. Therefore, the electronic parts constituting the oscillation circuit are arranged on the inner surface (inside the package) of the piezoelectric vibrator.
[0008]
In addition, in order to consider the consumption of electronic components as one of the cost reduction means, in a temperature compensated oscillator, an electronic component is mounted on a piezoelectric vibrator having a desired frequency characteristic to constitute an oscillator. As a result, it is possible to suppress the consumption of electronic components that occupy a large proportion of the total cost of the oscillator.
Therefore, it is possible to reduce the installation area on the mounting substrate compared to the conventional oscillator, and to reduce the cost by improving the yield of the piezoelectric vibrator with respect to the entire oscillator.
[0009]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings. In each figure, the same numerals indicate the same objects.
FIG. 1 shows a front view of the piezoelectric oscillator of the present invention. In FIG. 1, the piezoelectric oscillator has a hermetically sealed structure in which a piezoelectric vibrator 2 is mounted on the bottom of a recess of a package 1, the piezoelectric vibrator 2 is electrically connected by a conductive adhesive 7 or the like, and a shielding plate 5 is disposed on the top. Then, an oscillation circuit is mounted on the inner surface of the lid 3 (the space inside the sealed container is the inner surface through the lid) to constitute a piezoelectric oscillator having a sealed container structure.
[0010]
FIG. 2 shows a cross-sectional view of the structure of the package 1 of the present invention. Although not shown in FIG. 2, a conduction pattern is formed so that the oscillation circuit mounted on the lid 3 can be electrically conducted. A part of these conduction patterns is also connected to the piezoelectric vibrator 2 housed in the lid 3, and the piezoelectric vibrator 2 is used as a reference clock of the piezoelectric oscillator.
[0011]
In short, a sealed environment is constituted by the package 1 and the shielding plate 5, the piezoelectric vibrator 2 is accommodated therein, the electronic component 4 is added to the lid 3 of the package 1, and the piezoelectric vibrator 2 is electrically connected. Thus, the piezoelectric oscillator is configured, and the overall size of the piezoelectric oscillator can be reduced.
[0012]
Accordingly, the package is composed of an electronic component 4 which is an oscillation circuit (semiconductor etc.) component and a piezoelectric vibrator hermetically sealed by a shielding plate 5, and the piezoelectric vibrator 2 is mounted on the bottom of the recess of the package 1 and the lid 3 is covered. A conductive pattern is formed on the upper surface of the lid 3 and the electronic component 4 is mounted to constitute an electronic circuit to obtain a piezoelectric oscillator.
[0013]
In the present invention, the lid 3 of the piezoelectric vibrator 2 uses a ceramic material or a resin material, and the conductive pattern on the top surface of the lid 3 on which the electronic component 4 is mounted is formed by metal deposition or metallization processing (not shown).
[0014]
The conductive pattern is used to mount and electrically connect the electronic component 4, and forms an output part of the piezoelectric vibrator 2, and also is a drawer for conducting with the conductive pattern on the printed circuit board on which the piezoelectric oscillator is mounted. An electrode (terminal portion) is also formed, and the electronic component 4 and the conductive pattern are electrically connected by wire bonding 6, and the lid 3 and the package also constitute a sealed container (not shown conductive adhesive or solder). It has a structure in which electrical continuity is taken.
[0015]
In the present invention, in order to consider the consumption of the electronic component 4 as one of the means for reducing the cost, in the temperature compensated oscillator, the electronic component 4 is used only for the piezoelectric vibrator itself having a desired frequency characteristic. By mounting and configuring the oscillator, it is possible to suppress the consumption of the electronic component 4 that occupies a large proportion of the total cost of the oscillator.
Accordingly, it is possible to reduce the installation area on the mounting substrate compared to the conventional oscillator and to reduce the cost by improving the yield of the piezoelectric vibrator with respect to the entire oscillator.
Note that the piezoelectric vibrator described in this embodiment uses a piezoelectric material such as a quartz vibrator or ceramic.
[0016]
【The invention's effect】
According to the present invention, the mounting of the electronic components and the piezoelectric vibrator constituting the electronic circuit is reduced by reducing the mounting area of the piezoelectric oscillator itself by a package in which a piezoelectric vibrator having a satisfactory characteristic is covered with a lid on which the electronic circuit is mounted. We were able to. In addition, it was possible to reduce the cost of the entire oscillator by mounting an electronic component only on the piezoelectric vibrator itself having a desired frequency characteristic to constitute an oscillator.
[Brief description of the drawings]
FIG. 1 is a front view of the present invention.
FIG. 2 is a cross-sectional view of the package of the present invention.
FIG. 3 is a perspective view of a conventional temperature compensated oscillator.
[Explanation of symbols]
1 Package 2 Piezoelectric Vibrator 3 Lid 4 Electronic Component 5 Shielding Plate

Claims (1)

In the surface mount type package in which the piezoelectric vibrator is disposed at the bottom of the concave portion of the concave surface mount package for housing the piezoelectric vibrator and the electronic component, and the blocking plate is disposed on the piezoelectric vibrator, the blocking plate includes the piezoelectric vibration. A part of the concave portion in which the child is accommodated is sealed, and the electronic component is mounted on the lid of the package, the electronic component and the piezoelectric vibrator are electrically connected, and the electronic component is A surface-mount package comprising: a piezoelectric oscillator having the lid portion so as to be positioned above the piezoelectric vibrator.

Images