JPH0711028U - Surface mount type piezoelectric vibrator - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a more reliable surface mount type piezoelectric vibrator in which the bending of a piezoelectric plate such as a crystal due to an external impact is minimized and the piezoelectric plate is not damaged by the bending. Is. There is a base substrate 1 on which an extraction electrode to the outside is formed, and a support member (connection electrodes 3a, 3b and a support 4) for supporting the piezoelectric plate 5 is provided at least at both longitudinal end portions thereof. Piezoelectric plate 5 with excitation electrodes formed on the front and back surfaces
In a surface mount type piezoelectric vibrator in which the above is mounted, and a sealing lid is attached to the upper part of the base substrate for sealing, auxiliary supporting members 13b and 13c are provided at least near the periphery of the piezoelectric plate.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a surface-mounted piezoelectric vibrator, and more particularly to a piezoelectric plate holding structure that suppresses bending of the piezoelectric plate using quartz or the like.

[0002]

[Prior art]

 With the recent miniaturization of electronic devices, electronic components are required to be thin and low and to be mounted on a printed wiring board at a high density on the surface thereof. This is no exception in the field of crystal units, and recently thin-type surface mount type crystal units have been considered, and as shown in FIG. A crystal plate 5 having an excitation electrode 12 is directly mounted on the upper surface of an electrode pad 3 of a lead-out terminal formed on a substrate without using the support used, and a conductive bonding material is used. It was joined with. In addition, a support base 4 for eliminating the inclination of the crystal plate is provided at the facing portion of the electrode pad 3 according to the thickness of the electrode pad. The base substrate 1 and the sealing lid (not shown) are bonded to each other using, for example, low melting point glass to hermetically seal.

[0003]

[Problems to be solved by the device]

 However, in the above configuration, since the crystal plate is fixedly supported by the supporting member having no elasticity such as the electrode pad and the ceramic laminate, when a shock such as a drop is applied, the crystal plate 5 as shown in the cross-sectional view of FIG. Was largely bent, and the crystal plate 5 was sometimes damaged from the support portion 3 or 4.

An object of the present invention is to provide a more reliable surface mount type piezoelectric vibrator in which the bending of a piezoelectric plate such as a crystal due to an external impact is minimized and the piezoelectric plate is not damaged by the bending. Is.

[0005]

Therefore, the surface-mounted piezoelectric vibrator of the present invention has a base substrate on which external extraction electrodes are formed, and a support member for supporting the piezoelectric plate at least at both longitudinal end portions thereof. In a surface-mounted piezoelectric vibrator, which has a piezoelectric plate with electrodes formed on the front and back surfaces and is sealed by mounting a sealing lid on the upper part of the base substrate, an auxiliary support member is provided at least near the periphery of the piezoelectric plate. Provided

[0006]

[Action]

 Deflection of the piezoelectric plate caused by supporting both longitudinal ends of the piezoelectric plate with supporting members such as electrode pads and ceramic laminates that do not have elasticity is dropped due to the provision of auxiliary support members near the periphery of the piezoelectric plate. Even if a shock is applied, the bending of the piezoelectric plate can be minimized. Therefore, the piezoelectric plate is not damaged from the supporting portion.

[0007]

【Example】

 Next, the present invention will be described with reference to the drawings and taking a crystal oscillator as an example of a piezoelectric oscillator. FIG. 1 is a perspective plan view showing a first embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA of FIG. FIG. 3 is a perspective plan view showing the second embodiment. FIG. 4 is a perspective plan view showing the third embodiment. In addition, about the 1st, 2nd, 3rd, and 4th Example of this invention, the same number is attached | subjected to the same part. The base substrate 1 and the sealing lid 2 of the surface mount type crystal unit of the present invention are made of ceramic such as alumina. Then, terminals 1a and 1b for connecting to an external circuit are provided on the side surface in the longitudinal direction of the base substrate 1, and the upper surface of the base substrate 1 is electrically connected to the excitation electrodes 12 (the back surface is not shown) of the crystal plate 5. There are provided connection electrodes 3a and 3b. In addition, a support base 4 is provided at the opposite portion of the connection electrode to prevent the crystal plate from tilting in accordance with the thickness of the connection electrode. The external connection terminals 1a, 1b and the connection electrodes 3a, 3b are electrically connected by providing lead electrodes 13a, 13b. Therefore, the lead electrode 13b is formed so as to have a wide width so as to overlap the circumference of the crystal plate, and the connection electrode 3a is formed so as to overlap the circumference of the crystal plate in substantially the same manner as the lead electrode 13b. The dummy electrode 13c which is not connected to the above electrode is provided. These electrodes are formed slightly thinner than the thickness of the connecting electrodes 3a, 3b and the supporting base 4 to provide a step. This is because, for example, a tungsten metallization layer is formed on the upper surface of the base substrate 1, and a nickel plating layer is formed on the upper surface of the tungsten metallization layer by electrolytic plating. It is obtained by covering the upper surface with a mask and further forming a gold plating layer on the upper surfaces of the electrodes other than the extraction electrode 13b and the dummy electrode 13c. Then, a rectangular AT-cut quartz plate 5 on which the excitation electrode 12 is formed (the back surface is not shown) is mounted on the connecting electrodes 3a, 3b and 4 and joined by a conductive joining material 6, and then the base is formed. The sealing lid 2 is placed over the substrate 1 and bonded to the bonding portion 21 between the sealing lid and the base substrate with the low melting point glass 7 to hermetically seal. In the surface mount type crystal resonator thus formed, the extraction electrode 13b and the dummy electrode 13c function as an auxiliary support member.

Further, as shown in FIG. 3, the electrode as the auxiliary supporting member is formed such that the crystal plate 5 and the extraction electrode 13d and the dummy electrodes 13e and 13f overlap each other at both ends in the crystal plate longitudinal direction. As shown in FIG. 4 and FIG. 4, the electrode as an auxiliary support member is formed such that the crystal plate 5, the extraction electrode 13g and the dummy electrode 13h overlap each other near the central portion in the crystal plate longitudinal direction. May be.

In the embodiment of the present invention, the auxiliary supporting member is formed by forming the electrode. However, as shown in FIG. 4, the ceramic is laminated on the base substrate 1 in advance, and the auxiliary supporting member is partially formed on the base substrate. You may form 11a, 11b.

The thickness of the auxiliary member may be equal to or less than the thickness of the supporting member. However, if the thickness of the auxiliary supporting member is too thin, the distance between the crystal plate and the auxiliary supporting member becomes long. Since the crystal plate may bend during impact, it is necessary to design the auxiliary support member to have a certain thickness so that the distance between the crystal plate and the auxiliary support member is set short. .

[0011]

[Effect of device]

 Deflection of the piezoelectric plate caused by supporting both longitudinal ends of the piezoelectric plate with supporting members such as electrode pads and ceramic laminates that do not have elasticity is dropped due to the provision of auxiliary support members near the periphery of the piezoelectric plate. Even if a shock is applied, the bending of the piezoelectric plate can be minimized. Therefore, the piezoelectric plate is not damaged from the supporting portion, and a more reliable surface-mounted piezoelectric vibrator can be obtained.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a perspective plan view showing a second embodiment.

FIG. 4 is a perspective plan view showing a third embodiment.

FIG. 5 is a perspective plan view showing a fourth embodiment.

FIG. 6 is a perspective plan view showing a conventional example.

FIG. 7 is a cross-sectional view showing a conventional bending structure of a quartz plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Base substrate 1a, 1b ... Connection terminal 2 ... Sealing lid 3 ... Electrode pad 3a, 3b ... Connection electrode 4 ... Support stand 5 ... Crystal plate 12 ... Excitation electrodes 13a, 13b, 13d ... Extraction electrodes 13c, 13e, 13f ... Dummy electrodes

Claims (1)

[Scope of utility model registration request] 1. A base substrate having an external extraction electrode formed, a support member for supporting the piezoelectric plate at least at both ends in the longitudinal direction, and a piezoelectric plate having electrodes formed on the front and back surfaces. A surface-mounted piezoelectric vibrator in which a sealing lid is attached and sealed on an upper part of a base substrate, wherein an auxiliary support member is provided at least in the vicinity of the periphery of the piezoelectric plate.