JPH0588026U - Surface mount piezoelectric device - Google Patents

Abstract

(57) [Summary] [Purpose] The area of soldering to the wiring pattern of the printed circuit board can be increased, thereby obtaining high reliability, easy assembly at the time of manufacturing, and reducing cost. [Structure] An insulating plate 17 made of ceramic in which a plurality of terminals 13 are extended from a base 12 is attached to a base of a piezoelectric vibrator 11 and through holes 18 formed correspondingly to the terminals are provided so as to penetrate the terminals. A groove 19 formed on the outer surface of the insulating plate for accommodating the terminal and a baked metal thin film are provided in the groove.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a surface mount piezoelectric device having a simple structure and high reliability when mounted.

[0002]

[Prior Art]

 Recently, piezoelectric devices such as crystal resonators, filters, and crystal oscillators, which make use of the piezoelectric characteristics of inexpensive and high-performance quartz, are widely used in various electronic devices. For example, in the case of a quartz resonator, an artificial quartz crystal is cut into a plate shape by cutting it at a predetermined cutting angle with respect to the crystal axis, and electrodes are formed on this plate surface to excite piezoelectric vibration. There is. Such a piezoelectric device is assembled, for example, on a base into which lead terminals are planted, a metal lid is placed on the base, the opening is soldered to the periphery of the base, and resistance welding is performed to make it airtight. Sealed ones are most frequently used. On the other hand, recent electronic devices are desired to have a particularly small size and light weight, and efforts are being made to further reduce the manufacturing cost by automating the assembly process as much as possible. Therefore, active devices such as transistors and ICs and passive devices such as resistors and capacitors are often surface-mounted. This type of surface mount device is generally small in size and can be automatically arranged at a predetermined position on a printed circuit board using a parts feeder or the like. Then, after mounting all the components on the printed circuit board and passing them through a reflow oven to melt the solder applied to the terminals of each component, it can be mounted easily, with almost no human intervention. Electronic devices can be assembled and productivity can be significantly increased. For this reason, there is also a demand for a surface mount type piezoelectric device that is smaller in size and has no lead terminal than the one in which a lead terminal is led out by housing it in a metal container that has been widely used in the past.

By the way, such surface-mounted piezoelectric devices are roughly divided into two types. In the former case, the piezoelectric body is housed in a new container such as ceramic to hermetically seal it, and the electrode for surface mounting is formed on the bottom surface of the container. The latter is a metal container that has been used in the past and contains the piezoelectric material, and is designed so that the lead-out portion of the lead terminal can be modified for surface mounting. The former can be downsized to the utmost limit, and the structure can realize electronic components close to the ideal surface mount type. However, in such a case, there is a difficulty in that the airtightness, vibration resistance / shock resistance, and the like have few achievements. On the other hand, the latter has many years of experience in airtightness, vibration resistance and shock resistance, etc., and sufficient reliability has been proved for these, but it is a new structure because it is a surface mount type. It is necessary to add additional members, and sufficient consideration must be given to ease of assembly during manufacturing and reliability during mounting.

FIG. 4 is a perspective view showing an example of the latter surface-mounted piezoelectric device, and shows an example of a crystal resonator as the piezoelectric device. In the figure, reference numeral 1 denotes a base in which a pair of terminals 2 are implanted, and a holding member (not shown) provided at the tip of the terminals 2 holds the crystal piece. Then, the base 1 is covered with a metal cap 3 in an atmosphere such as vacuum or nitrogen gas, and soldered to the peripheral portion of the base 1 by resistance welding or the like to hermetically seal the base 1. An insulating plate 5 having a through hole 4 corresponding to each terminal 2 is provided, and the terminal 2 is inserted into the through hole 4 of the insulating plate 5 to attach the insulating plate 5 to the outer bottom surface of the base 1. Have been set up. Then, the electrode plates 6 are fitted to the distal ends of the terminals 2 which penetrate the insulating plate 5. The electrode plate 6 is a metal disc having a through hole 7 formed in the center thereof. The electrode plate 6 is fitted to the tip of the terminal 2 to hold the insulating plate 5 on the outer bottom surface of the base 1 and the electrode. The outer plate surface of the plate 6 is used as a mounting surface for surface mounting. However, in such a structure, for example, it is necessary to engrave a groove 8 in the circumferential direction at the tip of the terminal 2 so that the electrode plate 6 can be securely fitted to the tip of the terminal 2. The processing of the terminal 2 is also troublesome. Further, since the through hole 7 of the electrode plate 6 is formed with the slit 9 in the circumferential direction so that the terminal 2 can be elastically fitted to the tip end when the terminal 2 is inserted, the machining is troublesome and the cost is increased. There's a problem. Further, in such a case, there is a problem that the mounting state cannot be visually confirmed because it is difficult to externally confirm the soldering part of the electrode plate when the circuit board is mounted on the printed circuit board.

[0005]

[Problems to be solved by the device]

 The present invention has been made in view of the above circumstances, and it is possible to increase the area of soldering to the wiring pattern of the printed circuit board, thereby obtaining high reliability, easy assembly at the time of manufacturing, and low cost. It is an object of the present invention to provide a simple surface mount type piezoelectric device.

[0005]

[Means for Solving the Problems]

 The present invention comprises a piezoelectric vibrator in which a plurality of terminals are extended from a base, and an insulating plate made of ceramic in which each terminal is inserted into a through hole provided in the base and corresponding to each terminal. It is characterized in that it is provided with a groove formed on the outer surface of the insulating plate for accommodating the terminal, and a metal thin film baked in the groove portion.

[0006]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to a side sectional view shown in FIG. 1 and a bottom view of an insulating plate shown in FIG. In the figure, 11 is a crystal oscillator housed in a conventionally well-known metal container. A pair of terminals 13 are planted symmetrically in the major axis direction of the oval-shaped base 12 and perpendicular to the plate surface. A holding member 14 is provided. Then, both sides of the crystal piece 15 are sandwiched by the holding member 14, and the electrodes formed on the crystal piece 15 are led out to the outside through the holding member 14 and the terminal 13. Then, the base 12 is covered with a metal cap 16, and the opening of the cap 16 is soldered to the peripheral edge of the base 12 in an atmosphere such as vacuum or nitrogen gas, and resistance welding is performed to hermetically seal the base 12. .. An insulating plate 17 made of ceramic is formed into an oval shape corresponding to the shape of the base 12 described above. Through holes 18 are formed symmetrically in the major axis direction so as to penetrate the terminals 13 corresponding to the terminals 13. A groove 19 for accommodating the tip of the terminal 13 is formed on the outer side surface of the insulating plate 17 toward the outside in the major axis direction, and a metal thin film is baked in the groove 16. Then, the tip portion of the terminal 13 penetrating the insulating plate 17 is bent and housed in the groove 19 and soldered to the metal thin film formed here.

With such a structure, the insulating plate 17 is provided at the lead-out portion of the lead wire 13 by using a crystal resonator housed in a metal container that has been conventionally mass-produced and has a sufficient track record of use. Since it can be mounted on the surface, it has sufficient reliability for the crystal unit itself. Then, the lead-out portion of the lead terminal 13 may be inserted into the insulating plate 17 and the tip end thereof may be bent to be housed in the groove 19 of the insulating plate 17 for soldering, and the assembling work thereof is easy and the manufacturing process is easy. The productivity is also good. Then, for example, cream solder is applied to a predetermined position of the circuit pattern formed on the printed board, and the outer surface of the insulating plate is brought into contact with this to heat the solder, thereby melting the solder and easily mounting it. However, when the surface-mounted piezoelectric device of the above-described embodiment is mounted on a printed circuit board, solder reaches the metal thin film in the groove of the insulating plate 17, and the soldering state can be easily confirmed from the outside. There are advantages. The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the groove is formed in the major axis direction of the insulating plate, but it is needless to say that the groove may be formed in the minor axis direction. is there. Further, in the above-described embodiment, the crystal oscillator is described as an example of the piezoelectric device, but it can be applied to devices such as a piezoelectric oscillator and a piezoelectric filter, and the number of terminals is not limited to two, and three or more appropriate terminals can be used. Can be provided.

[0008]

[Effect of the device]

 As described in detail above, according to the present invention, it is possible to provide a surface-mounted piezoelectric device that has high reliability, is easy to assemble during manufacturing, and is inexpensive.

[0009]

[Brief description of drawings]

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

FIG. 2 is a bottom view of the insulating plate of the embodiment shown in FIG.

FIG. 3 is a perspective view showing an example of a conventional surface mount piezoelectric device.

[Explanation of symbols]

 11 crystal oscillator 12 base 13 lead terminal 15 crystal piece 16 cap 17 insulating plate 18 through hole 19 groove

Claims (1)

[Scope of utility model registration request] 1. A piezoelectric vibrator in which a plurality of terminals are extended from a base, and an insulating plate made of ceramic in which each terminal is inserted into a through hole provided in the base and corresponding to each terminal. A surface-mounted piezoelectric device, comprising: a groove formed on an outer surface of the insulating plate for accommodating the terminal; and a metal thin film baked in a portion of the groove.