JPH0487409A - Chip type piezoelectric resonator - Google Patents

Abstract

PURPOSE:To miniaturize a piezoelectric resonator by housing a piezoelectric body substrate provided with a vibration electrode in the groove of a mother board in a state that both end parts of the piezoelectric body substrate are supported by the bottom face of the groove, and cutting the mother board and a sealing plate at every piezoelectric body substrate so that both end faces are exposed on the cut-out surface. CONSTITUTION:In the mother board 1, two pieces of grooves 2 for housing the piezoelectric substrate are formed on its upper face, and vibration space formation recessed parts 3 are arranged at a prescribed interval so as to overlap this groove 2. Subsequently, the piezoelectric body substrate 5 is housed horizontally in a vertical line in the groove 2 of the board 1, and covered with a sealing plate 8 from the upper side. In such a manner, the recessed part 3 of the mother board 1 is sealed up tightly by a sealing agent 7 and the sealing plate 8 and a vibration space is formed. This mother board 1 is tacked to a stiffening plate material 9, thereafter, cut out at every piezoelectric body substrate 5 so that both end faces 5a of the piezoelectric body substrate 5 are exposed on the cut-out surface by a cutter 10. Accordingly, it is unnecessary to add the thickness portion of a side wall of a housing case to the length of a piezoelectric resonator as conventional, therefore, the piezoelectric resonator can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chip-type piezoelectric resonator used in oscillation circuits, filter circuits, etc.

Obedience! ”0L! 2. Description of the Related Art Conventionally, as this type of chip-type piezoelectric resonator, energy-trap type thickness-shear vibration resonators shown in FIGS. 7 and 8 have been known. In this resonator, one piezoelectric substrate 16 is housed in a storage case 19, and then a sealing lid 25 is fixed to the open end of the storage case 19. The piezoelectric substrate 16 is provided with vibrating electrodes 17a and 17b on its front and back surfaces. Extracting electrodes 2 are provided at both ends of the storage case 19.
3a, 23b are provided, and these electrodes 23a, 23b
and a vibrating electrode 17a of the piezoelectric substrate 16.

17b is fixed via solder 24 and electrically connected. External electrodes (A) are placed at both ends of this resonator.

(B) are provided in contact with the extraction electrodes 23a and 23b, respectively.

As described above, in the conventional piezoelectric resonator, the dimension is the length of the piezoelectric substrate 16 plus the thickness of the side wall of the storage case 19.
Since the structure had a longitudinal dimension, there was a limit to miniaturization.

Therefore, an object of the present invention is to provide a chip-type piezoelectric resonator having a structure that allows the piezoelectric resonator to be miniaturized.

In order to solve the problem more than a means for determining, the chip-type piezoelectric resonator according to the present invention has a groove for accommodating a piezoelectric substrate in a motherboard, and a recess for forming a vibration space that overlaps the groove. A piezoelectric substrate provided with a vibrating electrode is housed in a groove of the motherboard with both ends of the piezoelectric substrate supported by the bottom of the groove, and a seal is applied to a recess of the motherboard and both ends of the piezoelectric substrate. A sealed vibration space is formed by the sealing agent and a sealing plate that covers the opening surface of the recess, and the motherboard and the sealing plate are attached to each piezoelectric substrate so that both end surfaces of the piezoelectric substrate are exposed to the cutout surface. It is characterized by being cut out.

Construction-F In the above configuration, the motherboard and the sealing plate were cut out so that both end surfaces of the piezoelectric substrate were exposed on the cut-out surfaces, resulting in a structure in which the piezoelectric substrate was exposed on the sides of the chip-type piezoelectric resonator. The vibrating electrode can be connected to the external electrode at the exposed portion. Therefore, it is not necessary to add the thickness of the side wall of the storage case to the length of the piezoelectric resonator as in the conventional case, and the length ξ of the piezoelectric resonator and the length of the piezoelectric substrate become approximately equal.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, one embodiment of a piezoelectric resonator according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an exploded perspective view of a chip-type piezoelectric resonator in a motherboard state according to this embodiment. The motherboard 1 has two grooves 2 formed on its upper surface for accommodating piezoelectric substrates. Vibration space forming recesses 3 are arranged overlapping the groove 2 at regular intervals. The motherboard 1 is made of an insulating material with excellent heat resistance and solvent resistance, such as ceramics or resin.

The piezoelectric substrate 5 has already been cut for each resonator, and vibrating electrodes 6a and 6b are formed on its front and back surfaces. The material of the piezoelectric substrate 5 is BaTios or Pb (ZrTi).
A ceramic substrate or the like is used. The piezoelectric substrates 5 are housed horizontally in the grooves 2 of the motherboard 1 in vertical rows. That is, both ends of the piezoelectric substrate 5 are connected to the bottom surface 2a of the groove 2.
It is fully stored with support.

The piezoelectric substrates 5 may be slightly apart from each other or may be in contact with each other. Furthermore, a sealant 7 is applied to both ends of each piezoelectric substrate 5 (see FIG. 2).

This sealant may be either an insulating material or a conductive material.

Next, the motherboard 1 containing the piezoelectric substrate 5 is covered with a sealing plate 8 from above. In this way, motherboard 1
A completely sealed vibration space is formed by the recess 3, the sealant 7, and the sealing plate 8.

As shown in No. 2150, after the assembled motherboard 1 is temporarily attached to the backing plate material 9, the piezoelectric substrate 5 is cut out by the cutter 10 so that both end surfaces 5a of the piezoelectric substrate 5 are exposed on the cutting surface. I can do it.

FIG. 3 shows the appearance of the chip-type piezoelectric resonator after being cut out. By cutting out the motherboard 1 and the sealing plate 8, the motherboard 1 and the sealing plate 8 constitute a storage case 12 and a sealing lid 13. The end surface 5a of the piezoelectric substrate 5 and the vibrating electrodes 6a and 6b are exposed on the side surface of the storage case 12.

Next, as shown in FIGS. 4 and 5, external electrodes (A) and (B) are attached to the vibrating electrodes 6g and 6b exposed on the sides of the piezoelectric resonator, respectively, at both ends of the chip-type piezoelectric resonator. Formed in an electrically connected state. External electrodes (A), (B
) is formed by coating and baking a paste such as Ag or Ag-Pd, or by sputtering, vapor deposition, plating, or other methods.

The length of the thus obtained piezoelectric resonator is approximately equal to the length of the piezoelectric substrate 5, and the dimensions are smaller than the conventional piezoelectric resonator.

Note that the chip-type piezoelectric resonator according to the present invention is not limited to the embodiments described above, and can be variously modified within the scope of the gist.

The method of forming a sealed vibration space is not limited to the above embodiment. For example, before applying the sealant 7, a sealing plate 8 shown in FIG.
Alternatively, both ends of the piezoelectric substrate 5 may be sealed by injecting the same. This hole 8a can be removed later during cutting. However, the sealant injection hole may be provided in at least one of the motherboard 1 and the sealing plate 8.

Further, the piezoelectric substrates do not necessarily need to be arranged horizontally on the motherboard, but may be arranged vertically (with the width direction of the piezoelectric substrate set in the thickness direction of the motherboard). In this case, it is necessary to prepare a thick motherboard, and to make the grooves and recesses for forming the vibration space deeper in the motherboard than in the above embodiments.

Further, the piezoelectric substrate may be housed in the motherboard in the form of a unit substrate in which a plurality of resonators are arranged in tandem.

As described above, according to the present invention, the piezoelectric substrate is cut out from the motherboard sealing substrate so that both end surfaces of the piezoelectric substrate are exposed on the cutout surface, so that the piezoelectric substrate can be used as a chip-type piezoelectric resonator. The structure is exposed on the side, and the length of the piezoelectric resonator and the length of the piezoelectric substrate are approximately equal. Therefore, it is not necessary to add the thickness of the side wall of the storage case to the length of the piezoelectric resonator as in the conventional case, and the piezoelectric resonator can be made smaller.

[Brief explanation of the drawing]

1 to 5 show an embodiment of a chip-type piezoelectric resonator according to the present invention, in which FIG. 1 is an exploded perspective view of a motherboard state, FIG. 2 is a vertical sectional view illustrating a cutting method, and FIG. Figure 3 is a perspective view showing the piezoelectric resonator after cutting out, Figure 4 is a perspective view showing the external appearance of the product, and Figure 5 is the x-
It is a vertical cross-sectional view of x'. FIG. 6 is a perspective view showing another modification of the sealing plate. FIGS. 7 and 8 are an exploded perspective view and a vertical cross-sectional view, respectively, showing a conventional chip-type piezoelectric resonator. DESCRIPTION OF SYMBOLS 1... Motherboard, 2... Groove, 2a... Groove bottom surface, 3... Recessed part for forming vibration space, 5... Piezoelectric substrate,
5a... end face of pressure i-type substrate, 6a, 6b... vibrating electrode, 7... sealing agent, 8゜8゛... sealing plate, 12...
・Storage case, 13...Sealing lid. Patent applicant Murata Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. A groove for storing the piezoelectric substrate on the motherboard,
a recess for forming a vibration space that overlaps the groove;
A piezoelectric substrate provided with a vibrating electrode is stored in a groove of the motherboard with both ends of the piezoelectric substrate supported by the bottom of the groove, and a sealant is applied to the recess of the motherboard and both ends of the piezoelectric substrate. and a sealing plate that covers the opening surface of the recess to form a sealed vibration space, and the motherboard and the sealing plate are cut out for each piezoelectric substrate so that both end surfaces of the piezoelectric substrate are exposed to the cutout surface. A chip-type piezoelectric resonator characterized by: