JP4156738B2 - Surface mount type piezoelectric oscillator - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a container structure in which a conventional lead terminal type product can be easily made into a surface mount type lead structure by improving the container shape of a piezoelectric oscillator.
[0002]
[Prior art]
In recent years, piezoelectric vibrators are frequently used as reference signals for signal clocks in various electronic devices and industrial devices, and among the piezoelectric vibrators, particularly, crystal vibrators with low frequency stability and low component prices are used. In electronic and industrial equipment that uses quartz resonators, the quartz resonator and the oscillation circuit that drives the quartz resonator are housed in an integrated container in order to achieve a reduction in size of the device itself and high reliability. Small-sized crystal oscillators are manufactured and used.
[0003]
In a crystal oscillator that has been used in the past, a lead terminal is disposed on an insulating substrate, and an oscillation circuit substrate mainly composed of a semiconductor integrated circuit and a crystal resonator having a sealed structure are disposed, and a cover is placed on the quartz substrate. Thus, it is mounted on a printed circuit board on the electronic device or industrial device side, and functions as a clock signal source for the electronic device or industrial device by establishing conduction. Therefore, the lead terminal led out from the insulating substrate has a role of outputting a power source and an oscillation frequency for driving the oscillator.
[0004]
However, such a piezoelectric oscillator has a structure that is mounted on a predetermined portion of a printed circuit board, for example, by soldering a lead wire derived from the oscillator to a conductive pattern formed on a plate surface of the printed circuit board. In electronic devices, there are currently strong demands for a small size and light weight and for automating the assembly process as much as possible. For this reason, electronic components such as transistors, ICs and other semiconductor elements, resistors, capacitors, etc., are becoming the mainstream, and these electronic components are small and can be surface-mounted. (Using a feeder, robot, sorter, etc.) can be mounted at a predetermined position on the printed circuit board.
[0005]
Therefore, after mounting all the components on the printed circuit board, it is possible to assemble the electronic equipment without human intervention by passing the reflow furnace etc. and melting and mounting the solder applied to the terminals of each component. By doing so, productivity can be significantly improved. In such a background, a crystal oscillator is desired to be of a surface mount type having a small shape and no lead terminal, rather than a conventional lead terminal form.
[0006]
FIG. 3 is a side view showing a partial cross section of a conventional surface-mount crystal oscillator. In a conventional oscillator, a conductive pattern is formed on an insulating substrate, and an electronic component such as a semiconductor integrated circuit or a crystal resonator is mounted thereon to constitute an oscillation circuit. A terminal is led out from the board and connected to a conductive pattern formed on the board, and is mounted on and connected to an external printed board through the terminal. Further, the opening edge of the cover formed by molding a metal plate and the substrate are fixed by soldering to form a lead terminal which is electrically connected to the printed circuit board by the terminal.
[0007]
[Problems to be solved by the invention]
Regarding the problems to be solved, as described above, the electronic components that make up the oscillation circuit are in the surface mounting form. At present, the mounting of the oscillator itself on the printed circuit board is also shifted to the surface mounting type, and the mounting components other than the oscillator are the same. In addition, by simply passing the oscillator through a printed circuit board reflow oven, etc., by melting and mounting the solder applied to the (surface mount type) terminals, the assembly of electronic equipment can be done without human intervention, improving the mounting process. This realizes a base structure of an oscillator that achieves the above.
[0008]
However, with the recent changes in the piezoelectric parts (life cycle) and the current status of various types, the objective is to make the transition from the lead terminal form to the surface mount form by utilizing the oscillator components that are currently used as much as possible. To do.
[0009]
[Means for Solving the Problems]
The present invention utilizes an oscillation circuit (substrate) that has been used in the past, and forms a surface mount type oscillator in the form of a lead terminal.
The invention of the present application embeds a conductive terminal in the insulating base, and the end of the external conductive terminal protrudes horizontally with respect to the side surface of the insulating base to form a terminal shape that enables surface mounting, and the upper part of the insulating base An insulating spacer is arranged on the other end of the conduction terminal, an oscillation circuit board is mounted, a metal case is put on and joined to the insulating base, and a groove is formed in the longitudinal direction of the insulating base on the bottom of the insulating base. In this surface-mount type piezoelectric oscillator, the groove portion is subjected to a conductive treatment, and the groove portion and a ground terminal of the conductive terminals are connected .
Also the metal casing of the above structure are joined by the groove portion of the insulating base bottom is a surface mount type piezoelectric oscillator metal case itself also becomes the ground potential.
[0010]
Therefore, by placing the conventionally used oscillation circuit (substrate) on top of the insulating spacer of the present invention, it is possible to utilize a conventional oscillation circuit and change the lead terminal form to a surface mount type inexpensive base. The problem was solved by improving the system.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
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. An embodiment of the present invention will be described with reference to the perspective view shown in FIG. As shown in FIG. 1, a conductive terminal 2 (metal terminal) is molded into an L shape and embedded in an insulating base 1. The conductive terminal 2 comprises an insulating base 1 formed by integrating a conductive metal obtained by subjecting a conductive metal to nickel plating with an insulating material such as ceramic, resin, or glass. Therefore, the insulating base 1 has at least three terminals sufficient for the external lead-out terminals (power supply terminal, frequency output terminal) of the oscillator.
[0012]
An insulating spacer 3 is disposed on the insulating base 1. When the conventionally used oscillation circuit board 7 is mounted on the insulating spacer 3, it serves as an insulating plate so that the oscillation circuit board 7 and the insulating base 1 are not in direct contact with each other. There are no particular restrictions on the thickness and material of the material, but ceramic materials and resin materials that are currently commonly used are assumed.
[0013]
A conventional oscillation circuit board 7 is mounted on the insulating spacer 3 described above, and an external lead-out portion (power supply terminal, frequency output terminal) of the oscillation circuit board 7 is connected to the L-shaped conduction terminal 2 with solder or conductive bonding. The oscillator circuit is configured by connecting with the agent. In short, the conductive terminal 2 is embedded in the insulating base 1, and the end of the conductive terminal 2 protrudes horizontally with respect to the side surface of the insulating base 1 to form a terminal shape that enables surface mounting. An insulating spacer 3 is arranged on the upper part, an oscillation circuit is mounted on the other end of the conduction terminal 2, a metal case 4 is covered, and a tab 9 of the metal case 4 and the insulating base 1 are joined. The feature of the present patent is that the terminal shape is changed to a surface mount type using the oscillator circuit board 7 of the oscillator used conventionally (in the form of a lead terminal) as it is.
[0014]
Further, the surface mount type oscillator is configured by covering the insulating base 1 and the oscillation circuit board 7 (the electronic components to be mounted) with the metal case 4. Here, the insulating base 1 and the metal case of FIG. 2 (a) is a plan view of the insulating base 1, and FIG. 2 (b) is a partial sectional view of the vicinity of the ground terminal 6 of the insulating base 1. As shown in FIG. As can be seen from FIG. 2, the insulating base 1 and the metal case 4 are fixed by soldering or a conductive adhesive at a groove portion 5 extending in the longitudinal direction on the bottom surface portion of the insulating base 1.
[0015]
Accordingly, the groove portion 5 of the insulating base 1 is subjected to conduction treatment 8 by metal metallization or vapor deposition, and this groove portion 5 conduction portion is also connected to the ground terminal 6 among the conduction terminals described above. It is also a feature of the present invention that when the oscillator is mounted on the mounted circuit board 7, the ground potential of the mounted circuit board 7 covers the entire metal case 4 and is covered with the metal case 4 to enhance the shielding effect of the entire oscillator. This enhances the shielding effect of the oscillator, thereby greatly reducing harmonic noise and electromagnetic noise from inside or outside the oscillator.
[0016]
【The invention's effect】
As described above, according to the present invention, a conventionally used oscillation circuit board can be used and can be diverted to a small and surface mount type. Therefore, by combining the conventional parts, it is possible to improve the yield and reduce the product cost by simplifying the unification of parts and the management of parts.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of the present invention.
FIG. 2 is a plan view of an insulating substrate of the embodiment shown in FIG. 1 and a partial cross-sectional view in the vicinity of a ground terminal.
FIG. 3 is a side view showing an example of a conventional surface-mounted crystal oscillator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulation base 2 Conduction terminal 3 Insulation spacer 4 Metal case 5 Groove part 6 Ground terminal 7 Oscillation circuit board

Claims (2)

A conductive terminal is embedded in the insulating base, and the end of the conductive terminal protrudes horizontally with respect to the side surface of the insulating base to form a terminal shape that enables surface mounting, and an insulating spacer is formed on the top of the insulating base. The oscillation circuit board is mounted on the other end of the conductive terminal, and a metal case is put on and joined to the insulating base, and a groove is formed on the bottom surface of the insulating base in the longitudinal direction of the insulating base. conductive treatment is applied to the grooves, a surface mount type piezoelectric oscillator and ground terminal is characterized in that it is connected within the groove portion and the conductive terminal. 2. The surface-mount type piezoelectric oscillator according to claim 1, wherein the metal case is joined by the groove on the bottom surface of the insulating base, and the metal case itself is at ground potential.

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