JPS59148419A - Thickness shear piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To attain superminiaturization by utilizing the thickness of conductive adhesive and providing air gap between a substrate and a piezoelectric plate so as to improve vibration resistance and shock resistance of a piezoelectric oscillator. CONSTITUTION:Electrode films 22, 22' for starting are formed on upper and lower faces of a paper-tablet piezoelectric plate 21 having thickness shear oscillation, lead films 23, 23' for leading out exciting oscillation having conductivity are formed in a prescribed thickness at both ends on an insulating substrate 25 (ceramic or the like) to support the piezoelectric plate 21 in a prescribed thickness, the end part of the lead films 23, 23' is made to overlap the end part of the piezoelectric plate 21, both parts are fixed by inserting the conductive adhesives to the composite part, and an air gap 26 is provided between the said substrate 25 and the piezoelectric plate 21. Thus, since the piezoelectric plate 21 is held directly to the substrate 25 strongly, the shock resistance and vibration resistance of the piezoelectric oscillator are improved and the miniaturization is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thick-beam piezoelectric vibrator for use in micro-sized oscillators and the like.

Conventionally, as a thin-thickness piezoelectric vibrator (hereinafter simply referred to as a piezoelectric vibrator), there are those shown in FIGS. 1(a) and 1(b). The piezoelectric vibrator shown in FIG. 1(a) consists of a rectangular piezoelectric plate 11
This is achieved through sabots 1-13 and 13' (hereinafter simply referred to as supports) which also serve as excitation vibration extraction and holding the piezoelectric plate 11 to the cage pressure, and the piezoelectric vibrator shown in FIG. This is a structure in which a piezoelectric plate 15 (for example, a circular piezoelectric plate) is held by directly accommodating vertical supports (16, 16') on a substrate (for example, a Senminck substrate) 14 constituting an oscillation circuit.

For such a piezoelectric vibrator, the shape of the support is determined in consideration of workability and reliability such as vibration resistance and impact resistance when incorporating it into the piezoelectric plates 11 (151 is servo) 13, 13' (16, 16'). It's necessary.

However, workability and reliability have a contradictory relationship.

That is, in order to improve workability, it is necessary to make the support longer and larger, but reliability deteriorates significantly. In addition, it is necessary to select all cages with sufficient internal volume to prevent the piezoelectric plates and supports from coming into contact with the inner wall of the cage case, etc., which results in a large volume for a piezoelectric vibrator. As shown in FIG. 1(b), a piezoelectric plate 15 is provided with direct supports 16 and 16' on the substrate 14 constituting the oscillation circuit.
If this is installed, it will be difficult to study the current characteristics due to piezoelectric vibration and overdrive to the transducer. For this reason, improvements in the electrical characteristics of the piezoelectric vibrator itself are either completely ignored, or manufacturing variations (for example, adhesive trays used to bond the piezoelectric plate and support) are treated at a high level. A need arises to completely solve the problem of electrical characteristics. In addition, piezoelectric vibrators that are oscillated by an oscillation circuit and have a problem must be discarded together with the oscillation circuit, which has the disadvantage of low fractionation.

It is an object of the present invention to provide a chip-shaped piezoelectric vibrator with a uniform thickness, which eliminates the above-mentioned drawbacks, and which improves workability, reliability, and miniaturization.

The piezoelectric vibrator with a thickness of 9 according to the present invention has an insulating property '(+-
A conductive lead group for extracting excitation vibration is formed at both ends of the substrate, and the ends of the lead group and the ends of the piezoelectric plate having excitation electrode films on the upper and lower surfaces are overlapped to form a conductive bond. The piezoelectric plate is fixed with an intervening agent, and a gap is defined between the substrate and the piezoelectric plate.

Embodiments of the present invention will be described below based on the drawings.

FIG. 2(a) is a plan view showing a first embodiment of the present invention, and FIG. 2(b) is a front view of the same embodiment. This thickness-shear piezoelectric vibrator has excitation electrode films 22 and 22' formed on the upper and lower surfaces of a rectangular piezoelectric plate 21 having thickness-shear vibration, and an insulating substrate for holding the piezoelectric plate 21. (For example, ceramic, Si, crystal, etc.) 25 has a conductive lead film for extracting excited vibrations at both ends (For example,
A plating film such as Au r Ag + A I or a conductive adhesive 23 n' is formed to a predetermined thickness, and the end of the lead film 23 r 23' and the end of the piezoelectric plate 21 are overlapped. A conductive adhesive is interposed in this overlapping portion to fix the two, and a gap U is provided between the substrate 25 and the piezoelectric plate 21.

According to this embodiment, since the gap 26 is defined between the substrate 25 and the piezoelectric plate 21 by utilizing the thickness of the conductive adhesive 24, 24', the piezoelectric plate 21 is directly and firmly held by the substrate 25. Therefore, the vibration resistance and impact resistance of the piezoelectric vibrator are improved, and it is possible to achieve an ultra-small size in the form of a chip.

Furthermore, since the piezoelectric vibrator can be treated as a single unit, it is easy to improve current characteristics by overdriving and check electrical characteristics, and reliability can be improved.

FIG. 3(a) is a plan view showing a second embodiment of the present invention, and FIG. 3(b) is a front view of the same embodiment. 31 is a rectangular piezoelectric plate, 32.32' is an excitation electrode film, 33.33' is a lead group for extracting excited vibrations, 34.34' is a conductive adhesive, 35 is an insulating substrate, and 36 is a void. The corners of the rectangular piezoelectric plate 31 and the excitation vibration extraction leads [33, 3
3' end portions are overlapped and fixed with conductive adhesives 34, 34' interposed therebetween.

This embodiment also has the same effects as the first embodiment. It goes without saying that the same effect can be achieved not only with a strip-shaped piezoelectric plate or a rectangular piezoelectric plate but also with a circular piezoelectric plate.

FIG. 5 is a perspective view showing how the piezoelectric vibrator shown in FIG. 2 or 3 is used. A piezoelectric vibrator 56 is placed on a substrate 52 constituting an oscillation circuit, and The substrate 51 (25, 35)' is coated with conductive adhesive or solder 55.
This shows the joined state.

FIG. 4(a) is a plan view showing a third embodiment of the present invention, and FIG. 4(b) is a front view of the same embodiment. This piezoelectric vibration i
In the child, a strip-shaped piezoelectric plate 41 and a piezoelectric plate holding substrate 4
6 are the same size, and the thickness M of the plating film, the adhering film due to zufu-zoku or snow vines, etc. is made on the edge of the upper surface of the substrate 46.
43' and 44', and conductive leads N43 and 44 for extracting excitation vibration are formed on the lower surface of the substrate 46,
The piezoelectric plate 41 and the substrate 46 are fixed at their ends with conductive adhesive 45 and 45'.
Conductive adhesives 45 and 45' are interposed at both ends, and a gap 46 is defined between them.

According to the pressure vibrator of this embodiment, the lead film 43 for extracting excited vibrations provided on the lower surface of the substrate 46 can be bonded to the substrate constituting the 44-karat gold oscillator circuit in the same manner as chip components such as capacitors.

As described above, according to the present invention, the ends of the lead film and the ends of the pressure plate having excitation electrode films on the upper and lower surfaces are overlapped and fixed with a conductive bonding agent interposed therebetween, and Since the entire thickness of this conductive bonding agent is used to define an air source between the substrate and the piezoelectric plate, there is no need for conventional supports, and the piezoelectric plate is reinforced with the substrate, making it vibration resistant. , the impact resistance is improved, and since no support is involved, the wall gap and valley are minute, thereby reducing the volume of the piezoelectric vibrator and achieving ultra-miniaturization in the form of a chip. Furthermore, since the piezoelectric vibrator can be handled as a single unit, it is easy to improve the current characteristics by overdrive and check the electrical characteristics. It also has the advantage of being able to be handled in the same way as other chip components such as capacitors and resistors when mounted on ultra-small oscillators.

[Brief explanation of the drawing]

FIGS. 1(a) and (b) are perspective views showing conventional thickness-slide piezoelectric vibrators, and FIGS. 2(a) and (b) are respectively "
A plan view and a front view showing the first embodiment of the main party, Figure 3 (
a) and (b) are a plan view and a front view, respectively, showing a second embodiment of the present invention, and FIGS. 4(a) and (b) are a plan view and a front view, respectively, showing a third embodiment of the present invention. , and FIG. 5 are perspective views showing how the first or second embodiment is used. 11, 15, 21, 31, 41...piezoelectric plate,
12, IB...retainer, 13, i31.16
, 164...Support, 14, 52...Substrate constituting the pre-drilling circuit, 17, 17', 53, 54... Chip parts such as capacitors, 22, 22', 32,
32', 42,42'...Excitation electrode film, O, 2
3', 33, 33', 43.44... Lead film for extracting excited vibrations, 24.24', 34.34', 4
5.45'...conductive adhesive, 25, 35.46.
...Piezoelectric plate holding substrate, 26°36, 47...Gap, 43', 44'...Thick film for providing 9 gaps between the piezoelectric plate and the substrate, 51...Piezoelectric vibrator board, 55.
...Conductive adhesive or solder, 56...Piezoelectric vibrator. Applicant: NEC Corporation No. 21'! J Figure 3 Figure 5

Claims (1)

[Claims] A conductive lead group for extracting excitation vibration is formed on both ends of an insulating substrate, and the ends of the lead film and the end of a piezoelectric plate having excitation electrode films on the upper and lower surfaces are overlapped. 1. A thick-beam piezoelectric vibrator, characterized in that the piezoelectric vibrator is fixed with a conductive bonding agent interposed therebetween, and a gap is defined between the substrate and the piezoelectric plate.