JPH0725619U - Surface mount piezoelectric oscillator - Google Patents

Abstract

(57) [Summary] [Purpose] A lead frame is integrally molded with a cover and a terminal to facilitate processing, reduce cost, and facilitate assembly. [Structure] A base made of a molding material, in which a base portion of a lead frame terminal having a plurality of terminals formed in a central portion is arranged on a mounting surface, at least a part of which is embedded and retained in a bottom surface, and side walls rising from the bottom surface are formed. An insulating substrate having a plate surface facing the inner bottom surface of the base, a circuit to be connected to the outside connected to the tip of the terminal and held, and an electronic circuit mounted on the plate surface to form an oscillation circuit. And a piezoelectric resonator mounted on the insulating substrate and a cover formed on the lead frame and covering the base.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a surface-mounted piezoelectric oscillator having a simple structure and easy to manufacture and assemble.

[0002]

[Prior art]

 Recently, piezoelectric vibrators, especially inexpensive and high-performance quartz vibrators, are widely used as a reference for frequency, time, etc. in various electronic devices. In order to achieve compact size, high reliability, and maintain high-precision frequency, a large number of crystal oscillators have a small-sized crystal oscillator and an oscillation circuit consisting of a semiconductor integrated circuit housed together in a container. Manufactured and used. In this type of conventional crystal oscillator, for example, a quartz piece with an oscillation circuit made of a semiconductor integrated circuit and electrodes formed on a base made of an insulating substrate such as ceramic is placed on top of it, and then covered with a cover to make it airtight in a vacuum. It is designed to be sealed. In this way, the electrodes formed on the plate surface of the crystal piece can be shielded from the outside air, and the inside of the container can be kept chemically and physically stable for a long period of time. High accuracy can be maintained.

Further, in recent electronic devices, it is particularly desired that the shape is small and lightweight, and efforts are being made to automate the assembly process as much as possible. For this reason, active devices such as transistors and ICs, and passive devices such as resistors and capacitors are often of the surface mount type. This type of surface-mounted device can generally be made small in size and can be automatically arranged at a predetermined position on a printed circuit board by using a parts feeder or the like. After placing all the components on the printed circuit board, they are passed through a reflow oven or the like to melt the solder applied to the terminals of each component. In this way, the device can be easily mounted on the printed circuit board, so that the electronic device can be assembled with almost no human intervention, and the productivity can be remarkably improved. For this reason, there is a demand for a surface mount type crystal oscillator, which is smaller in size and has no lead terminal than a crystal oscillator in which a lead terminal is led out by accommodating it in a metal container which is often used.

FIG. 4 is a side sectional view showing an example of a conventional surface mount type crystal oscillator. Reference numeral 1 in the figure denotes a lead terminal formed by pressing a metal thin plate into a predetermined shape by etching or the like. Then, the base 2 is molded with a molding material such as epoxy synthetic resin, and the lead terminals are embedded and held in the base 2. The base 2 is provided with a substantially rectangular bottom portion 2a located on the mounting surface and a side wall 2b rising from the peripheral portion of the bottom portion 2a to a certain height, and one end of the lead terminal 1 is positioned on the mounting surface. The other end is located on the bottom of the base 2. Then, a conductive pattern having a predetermined shape is formed by etching or the like on the plate surface of the insulating substrate 3 made of ceramic or the like, and the conductive pattern is hermetically sealed in a semiconductor integrated circuit, C, R and a small metal container. An electronic circuit 4 such as a child is mounted to form an oscillation circuit. Then, the lead wire 5 is connected to the other end of the lead terminal 1 and connected to the conductive pattern of the insulating substrate 3 to electrically connect to the outside through the lead terminal 1. Then, the cover 6 formed by molding a thin metal plate or the like is placed on the base 2 to seal the base 2.

However, in such a structure, it is necessary to separately prepare the lead terminal 1 and the cover 6, and it is necessary to form each into a predetermined shape, so that the processing is troublesome and the cost is high. There was a problem. Further, in the assembly process, the work is troublesome because the cover is put on the base having a small shape, for example, a size of about 10 mm square.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables easy processing by integrally forming a cover and a terminal on a lead frame, and reduces the cost. It is an object of the present invention to provide a surface-mounted piezoelectric oscillator that is easy to assemble and easy to assemble.

[0007]

[Means for Solving the Problems]

 The present invention is a base made of a molding material in which a base portion of a lead frame terminal having a plurality of terminals formed in a central portion is arranged on a mounting surface, at least a part of which is embedded and retained in a bottom surface, and a side wall rising from the bottom surface is formed. A circuit to be connected to the outside is connected to the tip of the terminal and held, and an electronic component is mounted on the plate to form an oscillation circuit. A surface mount type piezoelectric oscillator comprising: an insulating substrate; a piezoelectric resonator mounted on the insulating substrate; and a cover formed on the lead frame and covered with the base.

[0008]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to the assembly perspective view shown in FIG. 1, the lead frame plan view shown in FIG. 2 and the oscillator external view shown in FIG. Reference numeral 11 in the drawing is a lead frame which is made of a thin metal plate of 42 nickel, kovar or the like, and has a plurality of terminals 11a formed from a plate frame-shaped frame toward the center of the plate surface by pressing, etching or the like. Reference numeral 12 denotes a base formed by molding a molding material such as epoxy synthetic resin into a rectangular dish shape. The outer surface of the bottom portion 12a of the base 12 is used as a mounting surface, and a side wall 12b rising from the peripheral edge of the bottom portion is formed. There is. Then, the base end side 11b of the terminal 11a is arranged on the mounting surface, at least a part of the base end side 11b is embedded and held in the bottom surface of the base 12, and the tip end portion is placed inside the base 12. I try to stand up at a right angle. Therefore, a part of the terminal 11a on the tip end side of the base 11b is embedded in the bottom surface of the base 12, the outer surface is exposed on the bottom surface, and a part is further extended to the side of the bottom surface. A cover 11b is formed on the lead frame 11 together with the plurality of terminals 11a, and the cover 11c is electrically connected to, for example, one of the terminals 11a having a reference potential. After molding the lead frame 11 with the base 12, a predetermined position of the base portion of the terminal 11a is cut with a press or the like to be cut off from the frame.

Then, a conductive layer such as a copper foil is attached to a plate-shaped insulating material such as a glass epoxy substrate or a ceramic substrate, and a conductive pattern such as a copper foil or the like is adhered to the conductive pattern of the insulating substrate 13 which is etched to form a conductive pattern. An electronic circuit 14 such as a circuit, a resistor and a capacitor, and a crystal oscillator 15 are mounted to form an oscillation circuit. The plate surface of the insulating substrate 13 faces the inner bottom surface of the base 12. A circuit to be connected to the outside of the insulating substrate 13 is electrically connected to the tip of the terminal 11a so as to be led out to the outside and held on the base 12. Then, the cover 11c formed on the lead frame 11 is bent at the same time when the terminal 11a is cut off from the frame, for example, so as to cover the insulating substrate 13 held by the base 12.

With such a configuration, the base portion of the terminal 11a extending from the bottom surface of the base 12 is located on the mounting surface, and by soldering this base portion to a conductive pattern of a printed circuit board (not shown), so-called surface mounting is performed. It can be performed. When the cover 11c is placed on the insulating substrate 13 held by the base 12, the cover 11c is electrically and mechanically connected to the terminals of the lead frame 11, so that the work is easy. Further, when the lead frame 11 having a desired shape is formed from a thin metal plate or the like, the cover 11c is simultaneously formed on a part of the lead frame 11, so that the lead frame 11 can be easily manufactured and the cost can be reduced.

[0011]

As described in detail above, according to the present invention, the terminals and the cover are formed on the lead frame, so that the overall cost is low and the assembly is easy. Can be provided.

[0012]

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view of the lead frame of the embodiment shown in FIG.

FIG. 3 is a perspective view showing the external appearance of the oscillator of the embodiment shown in FIG.

[Explanation of symbols]

 11 lead frame 11c cover 12 base 13 insulating substrate 14 electronic component 15 crystal unit

[Procedure amendment]

[Submission date] December 7, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Added

[Correction content]

FIG. 4 is a side sectional view showing an example of a conventional surface mount type crystal oscillator.

Claims (1)

[Scope of utility model registration request] 1. A lead frame in which a plurality of terminals are formed from a frame plate-shaped frame toward the center of the plate surface, and a base portion of the lead frame terminals is disposed on a mounting surface and at least a part of the lead frame is embedded in a bottom surface. A base made of a molding material that holds and forms a side wall that rises from the bottom surface, and a plate surface facing the inner bottom surface of the base, and a circuit to be connected to the outside connected to the tip of the terminal and the plate. An insulating substrate on which electronic components are mounted to form an oscillation circuit; a piezoelectric resonator mounted on the insulating substrate; and a cover which is formed on the lead frame together with the terminals and covers the base. A characteristic surface mount piezoelectric oscillator.