JPH0634329U - Surface mount piezoelectric resonator - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a surface-mounted piezoelectric resonator having a holding structure excellent in vibration resistance and impact resistance. [Configuration] A seal ring 22 is fixed to the opening edge of a bottomed box-shaped base 21 made of ceramic to form a mounting electrode 23 on the outer side of the bottom surface, and the mounting electrode 23 is electrically connected to the base 2.
(1) A holding electrode 24 is formed on the inner side of the bottom surface, a thin metal plate is formed into two folds, and a holding member 25 having a folded portion positioned outside is pressed against the holding electrode 24 by a pair of welding electrodes having a predetermined gap. An electric current is applied between the welding electrodes to weld the holding member 25, the piezoelectric piece 26 is placed on the upper surface of the holding member 25 and fixed by a conductive adhesive, and the excitation electrode formed on the plate surface is led out to obtain the above-mentioned seal. The lid 27 is welded and sealed to the ring 22 by seam welding.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a surface-mounted piezoelectric resonator, and more particularly to improvement of a piezoelectric piece holding structure.

[0002]

[Prior art]

 Recently, piezoelectric resonators are widely used as a reference for frequency, time, etc. in various electronic devices. In particular, quartz oscillators that use quartz as a piezoelectric body are used in large quantities because they have excellent chemical and physical properties, and in addition to advances in manufacturing technology, they are inexpensive and have high performance. Conventionally, as such a crystal oscillator, one having a structure as shown in FIG. 3 is known. That is, a thin metal plate such as Kovar is press-molded to obtain an oval base 1. Then, two terminals 2 are inserted into the base 1 and filled with an insulating material such as molten glass to insulate and hold each other. Then, the base end of a holding member 3 having a spring property such as a piano wire is wound around and fixed to the tip of the terminal 2, and the clip 4 is formed at the tip. Then, the crystal piece 5 is inserted between the facing surfaces of the holding member 3, the peripheral portion thereof is held by the clip 4, and a conductive adhesive is applied to fix the quartz piece 5. The base 1 is covered with a bottomed cylindrical cover 6 having an oval cross section and hermetically sealed by resistance welding or the like. The crystal piece 5 is formed into a plate by cutting a crystal of quartz at a predetermined angle with respect to the crystal axis. Then, electrodes are formed on the front and back plate surfaces by vapor deposition or the like, and the electrodes are led out to both ends, respectively, and the lead-out ends are sandwiched by the clips 4 and electrically connected to the terminals 2.

However, in recent years, it has been desired to reduce the size and weight of electronic devices and automate the assembly process. For this reason, surface mount type devices without lead terminals are being widely used in electronic parts such as resistors, capacitors and integrated circuits. When assembling electronic equipment using surface-mounting electronic components like this, for example, apply cream solder, etc. to the parts to be soldered, and use an automatic machine such as a chip mounter to place all the components in the prescribed positions on the printed circuit board. To place. Then, the printed circuit board is passed through a tunnel furnace or the like to heat and melt the solder, thereby significantly streamlining the mounting work of components. Therefore, this type of surface mounting is more difficult than the conventional electronic equipment that mounts components after mounting through-holes for inserting lead terminals of components on a printed circuit board. It can be automated easily, and the size and weight can be reduced. For this reason, piezoelectric vibrators used for such electronic devices are also desired to be surface-mounted type without lead terminals. However, in the case of a piezoelectric vibrator, it is necessary to store it in a hollow container in an airtight manner.Since the piezoelectric body is brittle, it is easy to break due to vibration, impact, etc., and there is a problem in using a strong holding structure. It is not easy to make it a surface mount type. FIG. 4 is a side sectional view showing an example of such a surface mount type piezoelectric vibrator, in which a mounting electrode 12 is formed on the outer bottom surface of a base 11 formed of an insulating material such as ceramic in a bottomed box shape. Inside, a pillow-shaped holding electrode 13 is formed so as to be electrically connected to the mounting electrode 12. Then, the piezoelectric piece 14 is placed on the holding electrode 13, for example, a conductive adhesive is applied and held, and electrical continuity is achieved. Then, the metal plate-shaped lid 16 is soldered to the seal ring 15 fixed to the upper end edge of the base 11 and welded to seal the lid. However, such a structure has a problem that the vibration resistance and the shock resistance are low because the vibration and the shock from the outside directly act on the piezoelectric piece.

[0004]

[Problems to be solved by the device]

 The present invention has been made in view of the above circumstances, and an object thereof is to provide a surface-mounted piezoelectric resonator having a holding structure having excellent vibration resistance and impact resistance.

[0005]

[Means for Solving the Problems]

 According to the present invention, a seal ring is fixed to the opening edge of a bottomed box-shaped base made of ceramic to form a mounting electrode on the outside of the bottom surface, and a holding electrode is formed on the inside of the bottom surface of the base by conducting to the mounting electrode. , A thin metal plate is folded in two, the folded-back portion is located outside, and a pair of welding electrodes with a predetermined gap are pressed against the holding electrodes to energize between the welding electrodes and weld the holding member. A piezoelectric piece is placed on the upper surface of the member, fixed with a conductive adhesive, and the excitation electrode formed on the plate surface is led out, and the lid is welded and sealed to the seal ring by seam welding. It is what

[0006]

【Example】

 Hereinafter, an embodiment of the present invention will be described in detail with reference to an assembled perspective view shown in FIG. 1 and a side sectional view shown in FIG. In the figure, reference numeral 21 denotes a bottomed box-shaped base made of ceramic, for example, 5.0 mm × 7.5 mm and a height of 1.2 mm. A rectangular seal ring 22 is fixed to the opening edge of the base 11, and a mounting electrode 23 is formed on the outer side of the bottom surface. The holding electrode 24 is formed inside the bottom surface of the base 11 so as to be electrically connected to the mounting electrode 23. The mounting electrode 23 and the holding electrode 24 may be formed by metallization or the like, or a thin metal plate may be formed into a predetermined shape and embedded. Reference numeral 25 denotes a holding member, which is formed by folding a thin metal plate of nickel silver or the like having a thickness of about 0.05 mm into two folds so that the folded back portion is located outside and one outer plate surface is placed on the holding electrode 24. To do. The holding member 25 is pressed against the holding electrode 24 by a pair of welding electrodes having a minute gap of about 1.0 mm so that the welding electrodes are energized and welded. Then, the piezoelectric piece 26, for example, a crystal piece is placed on the other outer plate surface of the holding member 25. The crystal piece 26 is formed by cutting a crystal of a crystal at a predetermined angle with respect to the crystal axis to form a plate and forming electrodes on the plate surface. The crystal piece 26 is placed on the holding member 25 and is made of a conductive adhesive or the like. It is fixed and mechanically held, and electrically connected. A lid 27 made of metal is placed on the seal ring 22 at the opening of the base 21 and welded by seam welding for sealing.

With such a configuration, the holding member 25 is folded back in two, one outer plate surface is welded to the holding electrode 24, and the piezoelectric piece 26 is placed on the other outer plate surface. Therefore, good elasticity can be obtained by utilizing the elasticity of the holding member 25 itself. Since the holding member 25 holds the piezoelectric piece 26, it is possible to maintain good resonance characteristics without damaging or changing the characteristics of the piezoelectric piece 26 due to external vibration or shock. You can

[0008]

[Effect of device]

 As described in detail above, according to the present invention, it is possible to provide a surface-mounted piezoelectric resonator that has good vibration resistance and shock resistance, is suitable for mass production, and has a small shape.

[0009]

[Brief description of drawings]

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

FIG. 2 is a side sectional view of the embodiment shown in FIG.

FIG. 3 is an assembled perspective view showing an example of a conventional crystal resonator.

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

[Explanation of symbols]

 21 Base 22 Seal Ring 23 Mounting Electrode 24 Holding Electrode 25 Holding Member 26 Piezoelectric Piece 27 Lid

Claims (1)

[Scope of utility model registration request] 1. A bottomed box-shaped base made of ceramic, a seal ring fixed to an opening edge of the base, a mounting electrode formed outside the bottom surface of the base, and a base electrically connected to the mounting electrode. A holding electrode formed on the inner side of the bottom surface and a thin metal plate are folded in two, the folded portion is located outside, and a pair of welding electrodes with a predetermined gap are pressed against the holding electrode to energize and weld between the welding electrodes. The holding member, a piezoelectric piece that is placed on the upper surface of the holding member and fixed with a conductive adhesive, and leads out the excitation electrode formed on the plate surface, and a lid body welded to the seal ring by seam welding. And a surface-mounted piezoelectric resonator.