JP2004153427A - Crystal oscillator for surface mounting - Google Patents

Abstract

An object of the present invention is to provide a surface-mounted oscillator which facilitates formation of a circuit pattern on a mounting substrate to be bonded to a back surface of a crystal unit, thereby improving productivity.
A circuit having a column at four corners of a bottom surface of a crystal unit, a circuit pattern formed on a bottom surface of the crystal unit or a mounting board connected to the column, and the circuit pattern including at least an IC chip. In the crystal oscillator for surface mounting having the elements arranged, the column is separately connected as a metal after the circuit pattern is formed. The metal is a column.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a crystal oscillator for surface mounting (hereinafter, referred to as a surface mounting oscillator) as an industrial technical field, and relates to a surface mounting oscillator that has been downsized.
[0002]
[Prior art]
[Patent Document 1] JP-A-2000-296611
[0003]
BACKGROUND OF THE INVENTION Surface mount oscillators are widely used as frequency and time reference sources, especially in portable electronic equipment, because of their small size and light weight. In recent years, further miniaturization has progressed and is in a further development stage.
[0004]
(Example of Prior Art) FIG. 3 is an exploded view of a surface mount oscillator for explaining a conventional example.
The surface mount oscillator includes a crystal unit 1 and a mounting substrate 2. The crystal unit 1 is formed by enclosing a crystal piece (not shown) in a container body 3 made of a laminated ceramic, covering the metal cover 4, and hermetically sealing. The container body 3 is made of a laminated ceramic and has external terminals (not shown) at the four corners on the bottom surface. The external terminals have, for example, a pair of crystal terminals electrically connected to a crystal blank at one set of diagonal portions and an earth terminal connected to the metal cover 4 at another set of diagonal portions.
[0005]
The mounting substrate 2 is made of a laminated ceramic having pillars 5 integrally formed at four corners of the flat plate 2a by firing. An external receiving terminal (not shown) corresponding to the external terminal is provided on the front end surface of the column 5. A circuit pattern (not shown) is formed on the surface of the flat plate 2a, and accommodates a circuit element such as an IC chip 6 and a capacitor 7 constituting an oscillation circuit and the like together with the crystal blank. Mounting terminals are provided on the four corners of the bottom surface of the flat plate 2a. Then, the external terminals of the crystal unit 1 and the external receiving terminals of the mounting substrate 2 are connected by soldering or the like to form a surface mount oscillator.
[0006]
Alternatively, as shown in FIG. 4, the circuit pattern is formed by integrally forming the pillars 5 at the four corners of the bottom surface of the container body 3 of the crystal unit 1 by firing. The tip surface of the pillar 5 has a mounting terminal to which a circuit pattern is connected. Then, a circuit element including the IC chip 6 is provided in the circuit pattern. In such a case, since the pillars 5 are provided at the four corners of the mounting substrate 2 or the crystal unit 1, a plurality of circuit elements can be provided by increasing the area of the flat plate 2a.
[0007]
[Problems to be solved by the invention]
(Problems of the prior art) However, in the surface mount oscillator having the above configuration, it is necessary to form a circuit pattern on the surface of the mounting substrate 2 or the bottom surface of the crystal unit 1. Generally, a conductor is applied by printing and is integrally fired together with a ceramic material. However, when the planar outer shape is further reduced, the pillar 5 becomes an obstacle, and printing on the circuit pattern becomes difficult. Then, when an accurate circuit pattern including a disconnection or the like cannot be formed, the circuit does not function as a surface mount oscillator, and there is a problem that productivity is reduced.
[0008]
(Object of the Invention) It is an object of the present invention to provide a surface mount oscillator which facilitates formation of a circuit pattern on a mounting board and improves productivity.
[0009]
[Means for Solving the Problems]
The present invention has a column at the four corners of the bottom surface of the crystal unit, and a circuit pattern is formed on the bottom surface of the crystal unit or a mounting board connected to the column, and at least the IC chip 6 is attached to the circuit pattern. In a crystal oscillator for surface mounting having a circuit element including the same, after the circuit pattern is formed, the column 5 is separately connected as a metal. The metal is a cylinder.
[0010]
Thus, a circuit pattern can be formed on the bottom surface of the flat crystal resonator or the surface of the mounting substrate, so that the circuit pattern can be easily formed. Since the column is made of a metal cylinder, positional deviation is prevented. Hereinafter, an embodiment of the present invention will be described.
[0011]
【Example】
FIG. 1 is a diagram of a surface mount oscillator illustrating an embodiment of the present invention. The same parts as those in the prior art are denoted by the same reference numerals, and description thereof will be simplified or omitted.
As described above, the surface mount oscillator is formed by bonding the mounting substrate 2 having the column 5 to the bottom surface of the crystal unit 1 having the external terminals at the four corners of the bottom surface. In this embodiment, the mounting substrate 2 includes a flat plate 2a made of ceramic and a column 8 made of metal.
[0012]
In such a device, first, after forming a circuit pattern by printing on the surface of the flat plate 2a, the metal cylinder 8 is connected to terminals (not shown) at the four corners by soldering or the like. Next, at least a circuit element such as an IC chip 6 and a capacitor is provided. Alternatively, after disposing the circuit elements, the metal cylinder 8 is connected. Finally, the metal cylinder 8 of the mounting substrate 2 is joined to the external terminals at the four corners of the bottom surface of the crystal unit 1. The metal column 8 may be connected to the mounting substrate 2 after joining to the bottom surface of the crystal unit 1.
[0013]
With such a configuration, since the mounting substrate itself is the flat plate 2a, it is easy to print a circuit pattern by a screen printing method using a mask. Therefore, the productivity of the surface mount oscillator is improved. In addition, since the column body is the column 8, there is no directivity in connection and the connection work is facilitated.
[0014]
[Other matters]
In the above embodiment, the metal cylinder 8 is provided on the mounting substrate 2. However, the metal cylinder 8 may be provided at the four corners by forming a circuit pattern to be connected to the circuit element on the container body 3 of the crystal unit 1. Also in this case, the printing of the circuit pattern is facilitated similarly to the embodiment, and the productivity can be improved. In addition, although the column was a column 8, it may be basically a prism. Further, although the pillar is made of metal, it includes a substantial conductor having a conductive path on the surface or inside of the insulator, for example. Further, although the mounting substrate 2 is made of ceramic, it may be made of glass epoxy or the like.
[0015]
【The invention's effect】
In the present invention, since a circuit pattern is formed on the bottom surface of the crystal unit 1 or on the mounting substrate 2 and the pillars are provided at the four corners, the circuit pattern can be easily formed and the productivity can be enhanced.
[Brief description of the drawings]
FIG. 1 is an exploded view of a surface mount oscillator illustrating one embodiment of the present invention.
FIG. 2 is an exploded view of a surface mount oscillator illustrating another embodiment of the present invention.
FIG. 3 is an exploded view of a surface mount oscillator illustrating a conventional example.
FIG. 4 is an exploded view of a surface mount oscillator illustrating another conventional example.
[Explanation of symbols]
1. Quartz crystal resonator, 2 mounting board, 3 container body, 4 cover, 5 pillars, 6 IC chip, 7 capacitor, 8 cylinders.

Claims (2)

A column is formed at the four corners of the bottom surface of the crystal unit, and a circuit pattern is formed on the bottom surface of the crystal unit or a mounting substrate connected to the column, and a circuit element including at least an IC chip is arranged in the circuit pattern. In the crystal oscillator for surface mounting provided, after the circuit pattern is formed, the column body is separately connected as a metal. 2. The crystal oscillator for surface mounting according to claim 1, wherein the metal is a cylinder.

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