JPH0525820U - Chip parts - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a chip component that prevents displacement of a contact position that supports a piezoelectric element, prevents fluctuation of frequency characteristics, stabilizes characteristics, and downsizes. [Structure] A case for accommodating a piezoelectric element in which vibrating electrodes are formed facing the front and back surfaces of a piezoelectric substrate, respectively, with a space from the inner surface, and the piezoelectric element is supported by a support portion having a small area on the front and back surfaces. It is composed of a leaf spring electrically connected to the vibrating electrode, a lead electrode formed on the inner surface of the case electrically connected to the leaf spring, and an external electrode formed on a side surface portion of the case outside which is electrically connected to the lead electrode.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a package type chip component in which a piezoelectric element made of piezoelectric ceramics is enclosed in a case. For example, a piezoelectric element used in a piezoelectric oscillator, a filter, a trap, a discriminator, etc. using area vibration is used. The present invention relates to a chip component that is held securely in a ceramic case and has stable piezoelectric resonator characteristics.

[0002]

[Prior Art]

 BACKGROUND ART Conventionally, piezoelectric chip parts such as piezoelectric oscillators, filters, traps, and discriminators, for example, chip parts in which a piezoelectric element using area vibration is housed in a case have hitherto been shown in FIG. Are known. This pseudo chip component 21 includes a piezoelectric element 22 having vibrating electrodes 24, 24 formed on the front and back surfaces of a piezoelectric substrate 23, a case 25 accommodating the piezoelectric element 22, and a terminal 27 bent outside. , 27. In the piezoelectric element 22, the node points at the central portions of the respective vibrating electrodes 24 on the front and back sides are used as the supporting portions 26, and the protrusions 27a of the terminals 27 are in contact with the supporting portions 26 on the front and rear surfaces, respectively. The piezoelectric element 21 is sandwiched between the terminals 27, 27 by the elasticity of the spring material by interposing a spring material between the terminals 25 and 25, and is pressed against the terminals 27, 27, and is held in the case 25. One end side of the terminals 27, 27 is exposed to the outside from the opening side of the case so that the terminals can be electrically connected to the outside, and the opening end is sealed with a resin layer 28. Then, the terminals 27, 27 are bent outside to form a pseudo chip type.

[0003]

[Problems to be solved by the device]

 However, in the above-mentioned conventional chip component, since the terminals are bent to form a chip type, the processing of the terminals is complicated, there is a limit to miniaturization, and the directionality must be maintained during mounting. there were. In addition, since the piezoelectric element is pressed and held via the terminals, the piezoelectric element is easy to move, and especially when the size of the piezoelectric element is large, the weight becomes large and it is easy to displace, and the contact position of the terminal is piezoelectric. There is a problem in that the device is displaced from the supporting part of the device and the frequency characteristic fluctuates, resulting in lack of stability. In addition, one end of the terminal is exposed to the outside from the opening side of the case so that it can be electrically connected to the outside, and the end of the opening is sealed with a resin layer, so the terminal metal and the sealing resin are different. There is a problem that heat resistance and moisture resistance are not good because the materials are joined.

The present invention has been made in view of the above problems of the prior art. It prevents displacement of the contact position, fluctuation of frequency characteristics, stability of characteristics, and miniaturization. The purpose is to provide measured chip parts.

[0005]

[Means for Solving the Problems]

 The chip component according to the present invention comprises a case for accommodating a piezoelectric element having a vibrating electrode formed on a front surface and a back surface of a piezoelectric substrate, respectively, at a distance from the inner surface, and a small area on the front surface and the back surface of the piezoelectric element. A leaf spring that is supported by the support portion of the case and that is electrically connected to the vibrating electrode, a lead-out electrode that is formed on the inner surface of the case that is electrically connected to the leaf spring, and a side surface portion that is outside the case and that is connected to the lead-out electrode It is characterized by comprising external electrodes.

[0006]

[Action]

 Since the chip component according to the present invention is configured as described above, the leaf spring is brought into contact with and held by the supporting portion of the piezoelectric element, and the conventional structure is not supported by the terminal. The contact position will not be displaced from the supporting portion of the piezoelectric element, and the frequency characteristics of the chip component will not change. In addition, the external electrodes are formed on the outer surface of the case without exposing the terminals to the outside, and they are electrically connected to the extraction electrodes on the inner surface, so the size is reduced and handling during mounting becomes easier. In particular, if a concave portion or a convex portion is provided at the abutting position of the piezoelectric element and the case so as to correspond to each other and the convex portion is fitted in the concave portion, the abutting position does not shift and the characteristics do not change. , Which is preferable for stable quality.

[0007]

Embodiment An embodiment of the present invention will be described below with reference to the drawings. 1 to 6 are views for explaining one embodiment. In the figure, 1 is a chip component according to the present embodiment. This chip component 1 is, for example, a piezoelectric element 2 having vibration electrodes 4 and 4 formed on the entire surface of the rectangular piezoelectric substrate 3 so as to face the front and back surfaces of the rectangular piezoelectric substrate 3, respectively, and supports for the front and back surfaces of the piezoelectric element 2. The leaf springs 6 and 6 supported by the portion 4a, the case 5 made of a member having the concave portion 7 formed on the inner surface, the extraction electrode 8 formed on the inner surface of the case and the extraction electrode 10 formed on the inner surface side of the lid 9. Side by side, it is composed of external electrodes 11, 11 and the like formed on the side surfaces of the case and lid 9 that face each other outside.

The piezoelectric element 2 is, for example, a rectangular piezoelectric substrate 3 made of piezoelectric ceramics such as PZT or lead titanate, and has rectangular vibration electrodes 4 and 4 facing each other on the front and back surfaces of the rectangular piezoelectric substrate 3, as shown in FIG. Are formed on the entire surface, and the support portions 4a are formed at the node points in the center. These supporting portions 4a, 4a are supported by the leaf springs 6, 6 and are electrically connected. As shown in FIG. 3, the leaf spring 6 has a bulge at the center and a top portion having a projection 12 that abuts and supports the support portion 4a of the piezoelectric element 2 so as to be elastically deformed. The leaf spring 6 is made of Ag-plated steel, nickel silver, phosphor bronze, or the like with good conductivity, and is electrically connected to each vibration electrode 4 and the extraction electrode 8 or 10. Further, it is preferable to provide a conductive elastic member such as a conductive rubber on the surface of the protrusion 12 to prevent the displacement at the contact point with the support portion 4a of the piezoelectric element 2.

As shown in FIG. 4, the case 5 has a substantially box-like shape, and a concave portion 7 is formed by lowering the inside and raising the circumference, and a convex portion 7 a is formed in the central portion of the wall that defines the concave portion 7. Then, a recess 6a is formed in the leaf spring 6 corresponding to this projection 7a so that the recess and the projection fit together. The piezoelectric element 2 is held by the leaf spring 6 and accommodated in the space formed by the recess 7 of the case 6. When the member 5a of the case 5 is made of insulating ceramics such as alumina having a proper strength, it has excellent heat resistance and moisture resistance. The external electrodes 11 and 11 to the case 5 are formed by lapping and cleaning the outer and inner electrode forming portions, then applying and baking a conductive paste, and then forming the extraction electrode 8 by sputtering or the like. As shown in FIG. 5, outer electrodes 11 and 11 are formed on both ends of the outer surface of the lid 9 by applying and baking a conductive paste, and lead electrodes 10 are formed on the inner surface side by sputtering or the like. The piezoelectric element 2 is supported by the leaf spring 6 and accommodated in the case 5, and the lid 9 is adhered and sealed with epoxy resin or the like (FIG. 6). Then, the end surfaces of the case 5 and the lid 9 are processed by sandblasting or the like to expose the extraction electrodes 8 and 10 well, and the external electrodes 11 and 11 of the case 5 and the lid 9 are connected at the end surfaces.

In the above embodiments, the piezoelectric substrate and the vibrating electrode are described as rectangular examples, but the shape is not limited to this. Although the case and lid have been described as being processed individually, a large number of large substrates may be processed. Further, the leaf spring is not limited to the above-mentioned embodiment, but it is preferable that the leaf spring is formed so as to be folded back at the end portion. By doing so, the leaf spring can be positioned in the case and a flat plate lid can be used.

[0011]

[Effect of the device]

 According to the present invention, since the node point of the piezoelectric element can be reliably supported and the supporting position can be prevented from shifting even if a considerable impact is applied, the frequency characteristic does not change and the characteristic is stable. Also, it can be made into a rectangular chip type and can be miniaturized, and the packaging density can be increased.

[Brief description of drawings]

FIG. 1 is a sectional view showing a chip part according to the present invention.

FIG. 2 is a plan view showing a piezoelectric element of this example.

3A and 3B are views for explaining a leaf spring of this embodiment, FIG. 3A is a plan view, and FIG. 3B is a sectional view taken along line AA of FIG.

FIG. 4 is a perspective view of a case of this embodiment.

FIG. 5 is a perspective view of a lid.

FIG. 6 is a perspective view illustrating a part of the manufacturing process of the chip part according to the present embodiment.

FIG. 7 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip component 2 Piezoelectric element 4 Vibrating electrode 4a Support part 5 Case 6 Leaf springs 8 and 10 Extraction electrode 11 External electrode

Claims (1)

[Scope of utility model registration request] 1. A case for accommodating a piezoelectric element having a vibrating electrode formed on a front surface and a back surface of a piezoelectric substrate, respectively, at a distance from an inner surface of the piezoelectric substrate, and a supporting portion of the piezoelectric element having a small area on the front surface and the back surface. It is composed of a leaf spring that supports and is electrically connected to the vibrating electrode, a lead-out electrode that is formed on the inner surface of the case that is electrically connected to the leaf spring, and an outer electrode that is connected to the lead-out electrode and that is formed on opposite side surfaces outside the case. Chip parts characterized by