Elastic surface wave element, elastic surface wave device using same and electronic instrument

Abstract

Provided is a surface acoustic wave device capable of realizing miniaturization and proper electrical characteristics. A surface acoustic wave element comprises an IDT (Inter-digital Transducer) electrode and a pad electrode formed in one main surface of a piezoelectric substrate and a ring electrode for earth formed in its periphery. In a surface acoustic wave device on which the surface acoustic wave element is mounted in a way the one main surface of the surface acoustic wave element was associated with a circuit substrate, at least one IDT electrode 30b and the ring electrode for earth are integrally formed.

Description

technical field [0001] The present invention relates to a surface acoustic wave device having an IDT electrode formed on one main surface of a piezoelectric substrate. [0002] Furthermore, the present invention relates to a surface acoustic wave device in which the surface acoustic wave element is mounted on a circuit board. [0003] Furthermore, the present invention relates to electronic equipment such as mobile communication equipment such as mobile phones, vehicle-mounted equipment, and medical equipment equipped with a surface acoustic wave device. Background technique [0004] Surface acoustic wave devices such as surface acoustic wave resonators and surface acoustic wave filters are widely used in various mobile communication devices, vehicle-mounted devices, and medical devices using microwave bands. miniaturization. [0005] As a conventional miniaturized surface acoustic wave device, for example, a structure in which a ring-shaped electrode for grounding surroun...

AI Technical Summary

Problems solved by technology

[0013] For the above reasons, it is difficult to achieve further miniaturization in conventional surface acoustic wave devices.

[0014] The second topic is the problem of electrical characteristics

[0018] The third problem is that it is difficult to achieve miniaturization and high reliability

If the disconnection of the resistance occurs, there is no part to avoid the charge excited by the pyroelectric effect, so it is impossible to prevent the discharge destruction of the IDT electrode due to the subsequent temperature change

In addition, Patent Document 2 shows that there is also a problem with the heat resistance of the thin film resistor material itself, and that oxidation rapidly progresses when the temperature rises, and there is a problem with reliability.

[0022] The fourth problem is that the prevention and control effect of the discharge damage of the IDT electrode is not sufficient

Therefore, the thermoelectric excitation on the input and output electrode pads is large and cannot be ignored

In addition, in such a ladder filter, the one-port resonator is constituted by the resonator electrodes, and the electrodes between the resonator electrodes of the signal lines connecting the input pad electrodes and the output pad electrodes cannot be grounded.

That is, the ground electrode cannot be sandwiched between the input pad electrode and the output pad electrode

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