Murata Manufacturing Co., Ltd.

Mitsuhiro Yamada

Hiroaki Kaida

Jiro Inoue

Kenichi Kotani

Masakazu Yoshio

Masaya Wajima

Takashi Hase

Hiroshi Kumano

Taiki Goto

Kaiza Makino

A quartz vibration element that includes: a quartz plate having first and second principal surfaces; first and second driving electrodes on the first and second principal surfaces, respectively, wherein when an X-axis, a Y-axis, and a Z-axis are defined as crystallographic axes of a quartz crystal of the quartz plate, an X'-axis and a Y′-axis are obtained by rotating the X-axis and the Y-axis about the Z-axis by a rotation angle φ, and a Y″-axis and a Z′-axis are obtained by rotating the Y′-axis and the Z-axis about the X′-axis by a rotation angle θ, the first and second principal surfaces are perpendicular to the Y″-axis, and when one of the first or second principal surfaces is viewed in plan and an angle ψ is between the X-axis and a long side of the quartz plate, the quartz plate satisfies both Ψ=α×φ×θ and −0.0165−0.016≤α≤−0.0165+0.016 or +0.0165−0.016≤α≤+0.0165+0.016.

Quartz vibration element and manufacturing method of quartz vibration element

An energy trap type piezoelectric resonator component includes a piezoelectric resonator using a third overtone of a thickness longitudinal vibration. The piezoelectric resonator includes a piezoelectric substrate, and first and second vibrating electrodes, having an elliptical shape, and respectively arranged on portions of first and second major surfaces of the piezoelectric substrate such that the first and second vibrating electrodes face each other with the piezoelectric substrate interposed therebetween. A flattening ratio 'a/b' of a minor axis diameter 'b' to a major axis diameter &#x201c;a&#x201d; of the elliptical shape is within a range of from about 1.2 to about 1.45. The resonator is thus compact, effectively controls the fundamental wave of the thickness longitudinal vibration as a spurious wave, is relatively free from area restraints of the electrode and dimensional constraints, and meets a variety of frequency requirements in a wide range.

Energy trap type piezoelectric resonator component

A piezoelectric resonator component includes an energy-trapped piezoelectric resonator utilizing a third order harmonic wave of thickness longitudinal vibration and including a piezoelectric substrate having first and second major surfaces and polarized in a direction of thickness between the first and second major surfaces, and first and second vibrating electrodes opposed to each other with the piezoelectric substrate interposed therebetween, and first and second casing substrates respectively laminated on the first and second major surfaces of the piezoelectric resonator so that cavities are arranged so as not to interfere with vibration of a vibration section where the first and second vibrating electrodes face each other through the piezoelectric substrate. The first and second vibrating electrodes are dimensioned so that the difference between the peak values of the phases of S0 and S1 modes of the fundamental wave of the thickness longitudinal vibration falls within a range of about &#xb1;5 degrees.

Piezoelectric resonator component

An energy-trap thickness extensional vibration mode piezoelectric resonator uses a harmonic of a thickness extensional vibration mode and effectively suppresses generation of unwanted spurious vibrations. The energy-trap thickness extensional vibration mode piezoelectric resonator includes a piezoelectric strip, first and second excitation electrodes located on opposite surfaces of the piezoelectric strip, and an internal electrode disposed inside the piezoelectric strip. The first and second excitation electrodes are located on opposite ends of the piezoelectric strip in an overlapping arrangement. The internal electrode is located opposite to the first and second excitation electrodes. The first and second excitation electrodes overlap each other over a length of l such that l/d is not greater than about 6, where d&equals;t/n.

Thickness extensional vibration mode piezoelectric resonator

A thickness extensional piezoelectric resonator includes a substantially rectangular piezoelectric strip, first and second excitation electrodes disposed on both surfaces of the piezoelectric strip, and an internal electrode disposed inside the piezoelectric strip. The first and second excitation electrodes are located on opposite sides of the piezoelectric strip. The internal electrode is located opposite to the first and second excitation electrodes. Assuming that the piezoelectric plate has a width W and a thickness t, the piezoelectric plate is constructed such that W/d is less than about 6.1 if d=t/n.

An energy-trapping piezoelectric resonator vibrates in a third-order wave of a thickness-extension vibration mode. The piezoelectric resonator includes a piezoelectric substrate polarized along its thickness. A ratio of the width W to the thickness T of the substrate is determined to be about 0.88.+-.5%, 1.06.+-.4%, 1.32.+-.5%, 1.80.+-.3%, 2.30.+-.3%, 2.69.+-.3%, 3.16.+-.2%, or 3.64.+-.2%. First and second electrodes are respectively disposed on the obverse and reverse surfaces of the substrate to cover the entire width and opposedly face each other at the central portion of the substrate in the longitudinal direction so as to form a resonance portion between the first and second electrodes. It is thus possible to obtain a piezoelectric resonator which does not require a large extra area of the substrate around the resonance portion and which exhibits good resonance characteristics by effectively suppressing unwanted spurious responses in a range between and near the resonant frequency and the anti-resonant frequency.

Energy-trapping piezoelectric resonator

An energy-trap thickness extensional vibration mode piezoelectric resonator utilizes a harmonic of a thickness extensional vibration mode achieves excellent resonant characteristics that are hardly affected by portions of the resonator which are physically supported. The energy-trap thickness extensional vibration mode piezoelectric resonator includes a piezoelectric strip, first and second excitation electrodes located on opposite surfaces of the piezoelectric strip, and an internal electrode disposed inside the piezoelectric strip. The first and second excitation electrodes are located on opposite ends of the piezoelectric strip in an overlapping arrangement. The internal electrode is located opposite to the first and second excitation electrodes. The resonator is designed so that a ratio L/d is not less than about 14, where L is the dimension of the piezoelectric strip 2 in the longitudinal direction, t is the thickness, and d=t/n.

A thickness extensional piezoelectric resonator utilizes harmonics of a thickness extensional vibration mode and has a significantly reduced size and significantly increased capacitance while not being susceptible to the effects of the stray capacitance of a circuit board upon which the resonator is mounted. The resonator includes a piezoelectric strip, first and second excitation electrodes located on one of two respective major surfaces of the piezoelectric strip, and internal electrodes disposed inside the piezoelectric strip. The first and second excitation electrodes are located on opposite sides of the piezoelectric strip. The internal electrodes are located opposite to the first and second excitation electrodes to thereby define a vibrating portion. Vibration-attenuating portions are located on opposite sides of the vibrating portion only along the longitudinal direction of the piezoelectric strip. No vibration-attenuating portions are located in the lateral direction of the piezoelectric strip.

Growing community of inventors

Shiga-ken, Japan

Mitsuhiro Yamada