JPS633485B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite piezoelectric component in which a resonator or filter and a resistor are formed on a thin plate that is an integrated piezoelectric ceramic plate and a thin plate made of a resistive material.

Piezoelectric resonators and piezoelectric filters that utilize so-called thickness vibrations (thickness vertical vibrations and thickness shear vibrations) are used as small, unadjusted circuit components that operate in the high frequency range of 1MHz or higher. These components are often used in circuits by connecting resistors in series or in parallel.

Generally, a separate resistor is externally connected to the piezoelectric resonator or piezoelectric filter, which is extremely disadvantageous in terms of miniaturization of the circuit.

As a means to solve this problem, conventionally, as shown in FIG. 1, a composite component in which a filter and a resistor are formed on a single piezoelectric ceramic plate 1 has been used. This composite piezoelectric component is manufactured as follows.

That is, a pair of divided electrodes 2 and 3 are attached to the front surface of one piezoelectric ceramic plate 1, and one partial electrode is attached to the opposite back surface to form a filter. A resistor 6 is provided between the electrodes 4 and 5 for taking out electrical terminals of this filter by coating carbon with screen printing or the like.

However, when this method uses screen printing to apply carbon, the piezoelectric ceramic plates used in high-frequency piezoelectric resonators and piezoelectric filters become extremely thin, so the pressure during printing can cause the elements to break. It had the disadvantage of being easy to use. Another problem was that the filter characteristics deteriorated due to the heat of 200 to 250° C. when baking the carbon.

The present invention provides a very compact piezoelectric composite component that eliminates the drawbacks mentioned above.

Hereinafter, the piezoelectric composite component of the present invention will be explained with reference to FIGS. 2 and 3.

Piezoelectric ceramic filter for FM intermediate frequency
CF is often used with a resistor connected around it, as shown in FIG.

FIG. 3 shows a composite piezoelectric ceramic filter in which the resistors R ₁ to _{R 3} shown in FIG. 2 are integrated with a piezoelectric ceramic filter CF. FIG. 3A is a front perspective view of the composite piezoelectric ceramic filter, and FIG. 3B is a back perspective view thereof. In the figure, a thin carbon resistor 1 is attached to the side surface of a piezoelectric ceramic plate 11.
2 and 13 are bonded together via adhesive layers 14 and 15, respectively, to form a composite piezoelectric ceramic plate. A pair of divided electrodes 16 and 17 are attached to one main surface of the piezoelectric ceramic plate 11, and one partial electrode 18 is attached to the other main surface opposite thereto. A filter CF is formed by these electrodes 16, 17, 18 and the portion of the piezoelectric ceramic plate 11 sandwiched therebetween. Further, a partial electrode 19 is attached to one main surface of the carbon resistor 12, and a partial electrode 20 is attached to the other main surface, and the carbon resistor 12 is sandwiched between the electrodes 19, 20 and these. By the resistor R ₁ in Fig. 2
is formed. Similarly, partial electrodes 21 and 23 are attached to one main surface of the carbon resistor 13, and partial electrodes 22 and 24 are attached to the other main surface of the carbon resistor 13. The resistors R ₂ and R ₃ shown in FIG. 2 are formed by the carbon resistors. Piezoelectric ceramic filter CF and resistor
R ₁ , R ₂ , R ₃ are electrodes 25, 26, 27, 28, 2
9 is connected as shown in FIG. 2, and the terminal 10
0,200,300,400 are taken out to form a composite piezoelectric component.

Next, a specific example of the present invention will be described using a piezoelectric filter as an example.

Ceramic material that can excite thickness-shear vibration as a piezoelectric ceramic plate (Matsushita Electric trademark PCM)
was used. To make a filter that operates at 10 MHz, a piezoelectric ceramic plate was polished to a thickness of 125 μm to create a rectangular element with an outer diameter of 0.5 × 3 mm ² . Two 0.5×2 mm ² thin plate carbon resistors containing resin were adhered to this rectangular element using a two-component epoxy resin adhesive at 130° C. for 4 hours. The required electrodes are attached to both main surfaces of this composite piezoelectric ceramic plate by bonding the piezoelectric ceramic plate and the resistor by vapor deposition, and the R ₁
= 470Ω, R ₂ = 100Ω, R ₃ = 2.2kΩ and one filter was constructed.

A composite piezoelectric component including a 10 MHz filter and a peripheral resistor can be constructed using a very small element of 0.5 x 7 mm ² made as described above.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of a conventional composite piezoelectric component, FIG. 2 is a diagram showing an example of a circuit configuration of a composite component according to the present invention, and FIG. 3A is an embodiment of the circuit configuration of FIG. 2. A perspective view of the front side of one embodiment, and FIG. 3B is a perspective view of the back side thereof. 11... Piezoelectric ceramic plate, 12, 13... Resistor, 14, 15... Adhesive layer, 16-29... Electrode, 100-400... Electric terminal.

Claims (1)

[Claims] 1. A piezoelectric ceramic plate excited by thickness vertical vibration or thickness shear vibration and a thin plate made of carbon resistance material are joined together on the side surfaces via an adhesive layer to form a resonator or filter on the piezoelectric ceramic plate. A composite piezoelectric component characterized in that a resistor is formed in a thin plate made of the above-described resistive material.