Abstract: A multilayer backing absorber for use with an ultrasonic transducer comprises a plurality of absorber elements, each absorber element having at least one metal layer and at least one adhesive layer, wherein the backing absorber is adapted to be coupled to a vibrating layer of the ultrasonic transducer.

Abstract: Provide an electronic component that has a hollowed structure and is capable of suppressing the deformation of the hollowed structure due to the pressure during the module resin molding. The electronic component includes a device substrate 2, a driver portion 3 formed on one of the principle surfaces of the device substrate 2, a protection portion 4 configured to cover the driver portion 3 so as to form a hollowed space 8 around the driver portion 3, an adhesion layer 10 that is made of a resin and arranged above the protection portion 4, and a reinforcing plate 11 arranged on the adhesion layer 10, wherein the reinforcing plate 11 is a silicon substrate.

Abstract: An elastic wave filter device includes serial and parallel arms and a plurality of elastic wave resonators. Each elastic wave resonator includes an IDT electrode. In the case where a direction in which electrode fingers extend is taken as a width direction of the IDT electrode, the IDT electrode includes a central area at a center in the width direction, a low acoustic velocity area at an outer side portion of the central area, and a high velocity area at a farther outer side portion thereof. A width of the low acoustic velocity area of at least one elastic wave resonator differs from a width of the low acoustic velocity area of the other elastic wave resonators.

Abstract: A piezoelectric unit 1 includes a piezoelectric element that causes thickness shear vibration, a first electrode provided on one surface of the piezoelectric element, a second electrode and a third electrode which are provided on an opposite surface to the one surface which is provided with the first electrode of the piezoelectric element and are electrically insulated from each other, and a switching portion that is connected to the first electrode, the second electrode, and the third electrode, in which the switching portion can switch measurement modes between a mass/viscoelasticity measurement mode for measuring mass of a substance which is in contact with the piezoelectric element or viscoelasticity by vibrating the piezoelectric element, and an electrical characteristic measurement mode for measuring electrical characteristics between the second electrode and the third electrode.

Abstract: A method for producing an electronic component module prevents a space from collapsing. The method includes a step of preparing an electronic component including an element substrate, a drive device formed on a principal surface of the element substrate, and a protection device covering the drive device so as to form a space around the drive device; a step of fixing the electronic component on a common substrate such that a principal surface of the common substrate and another principal surface of the element substrate face each other; a step of fixing a reinforcing plate on the protection device of the electronic component; and a step of forming a resin layer on the principal surface of the common substrate such that the electronic component is contained therein.

Abstract: A duplexer includes an antenna terminal, a transmission amplifier terminal and a reception amplifier terminal. The transmission amplifier terminal is coupled to the antenna terminal via a transmission filter. The reception amplifier terminal is coupled to a reception filter and the reception filter is coupled to the antenna terminal via a band-stop filter.

Abstract: An acoustic resonator device includes a bottom electrode disposed on a substrate over an air cavity, a piezoelectric layer disposed on the bottom electrode, and a top electrode disposed on the piezoelectric layer, where an overlap between the top electrode, the piezoelectric layer and the bottom electrode over the air cavity defines a main membrane region. The acoustic resonator device further includes at least one air-ring defining a boundary of the main membrane region, and at least one first frame formed between the bottom electrode and the piezoelectric layer or formed between the substrate and the bottom electrode, and a second frame formed between the piezoelectric layer and the top electrode.

Abstract: An ultrasonic transducer includes a substrate, a supporting film disposed on the substrate, and a piezoelectric element disposed on the supporting film. The substrate includes an opening. The piezoelectric element is disposed on an area that overlaps the opening in a plan view in a thickness direction of the substrate. A thickness of the supporting film at an area that overlaps the piezoelectric element in a plan view of the supporting film is smaller than a thickness of the supporting film at a different area different from the area that overlaps the piezoelectric element.

Abstract: An acoustic resonator structure comprises a first electrode disposed on a substrate, a piezoelectric layer disposed on the first electrode, a second electrode disposed on the piezoelectric layer, a frame disposed within a main membrane region defined by an overlap between the first electrode, the piezoelectric layer, and the second electrode, and having an outer edge substantially aligned with a boundary of the main membrane region, and a collar formed separate from the frame, disposed outside the main membrane region, and having an inner edge substantially aligned with the boundary of or overlapping the main membrane region.

Abstract: An acoustic wave bandpass filter comprises at least an input first acoustic wave resonator with an output surface, and an output second acoustic wave resonator with an input surface, said resonators being coupled to each other along a set direction, the input and output surfaces being substantially opposite, and at least one first phononic crystal structure between said input and output resonators and/or a second phonic crystal structure at the periphery of said resonators so as to guide the acoustic waves, generated by said input resonator, toward said output resonator along said set direction, the resonators ensuring an impedance conversion and/or a mode conversion.

Abstract: In a quartz crystal unit, the unit comprising a quartz crystal resonator having an overall length less than 2.1 mm, and a base portion, and first and second vibrational arms, at least one groove being formed in at least one of opposite main surfaces of each of the first and second vibrational arms so that a width of the at least one groove is greater than or equal to a distance in the width direction of the at least one groove measured from an outer edge of the at least one groove to an outer edge of the corresponding one of the first and second vibrational arms and less than 0.07 mm, at least one metal film for adjusting an oscillation frequency of the quartz crystal resonator being disposed on at least one of the opposite main surfaces of each of the first and second vibrational arms.

Abstract: A resonator includes: a package; a support section that is provided on a surface of the package; and a vibration element in which an attachment section, which is disposed between an outer edge of a vibration substrate, in which excitation electrodes are provided on main surfaces thereof, and an outer edge of the excitation electrode, is attached to the support section through a conductive adhesive. The attachment section is disposed in a region S obtained by rotating a virtual line which connects the center of the vibration element and one end of the vibration element, in a range of ?35° to +35° of a rotation angle ? about the center, and an attachment area becomes 0.7 mm2 or more.

Abstract: A liquid ejecting head includes a plurality of pressure generators each including a first electrode individually provided therefor, the first electrode being located on a face of the flow path plate so as to correspond to one of the pressure chambers, a piezoelectric layer provided on the first electrode, and a second electrode provided on the piezoelectric layer; a lead electrode electrically connected to the first electrode; and a conductive layer provided in a section where the first electrode is partially exposed, the section being located in a region where the second electrode is not provided and the piezoelectric layer is exposed, at least a part of the conductive layer being in contact with the first electrode. The lead electrode is connected to the first electrode via the conductive layer.

Abstract: A vibrating element as an element on which a base part, a supporting part extending from the base part, and adjustment electrodes as mass adjustment parts are provided and a semiconductor substrate as a circuit element are provided, and the adjustment electrodes are placed in locations not overlapping with the semiconductor substrate in a plan view, the supporting part and the semiconductor substrate are connected, and thereby, the vibrating element is mounted on the semiconductor substrate.

Abstract: A groove in which a curable resin is filled, is formed on the opposite side face of a face for reflecting light of an oscillating mirror unit. The groove extends so as to cross the swing axis of the oscillating mirror unit, seen from the opposite side of the reflection face of the oscillating mirror unit.

Abstract: There is provided a piezoelectric vibrating piece including: a piezoelectric plate that includes a pair of vibrating arm portions, and a base portion which integrally fixes the base end portions of the pair of vibrating arm portions along a length direction; excitation electrodes which are formed on the vibrating arm portions and vibrate the vibrating arm portions; mounting electrodes which are formed on the base portion and mount the piezoelectric plate on external portions using a joining member; and leading-out electrodes which connect the excitation electrodes and the mounting electrodes, in which the leading-out electrodes are formed by folding back several times between the excitation electrodes and the mounting electrodes.

Abstract: A double-side tuning fork-type bending vibration piece having a basal part, a pair of drive vibration arms, a pair of detection vibration arms, drive electrodes and detection electrodes includes adjustment films of a metallic material or the like formed in connecting areas between the vibration arms and the basal part. The adjustment films are formed in such a way as to cover an area of tapered portions formed in connecting parts between the drive vibration arms and the basal part, an area of the basal part near the tapered portions and an area of the drive vibration arms. While monitoring a detection current outputted from the detection electrodes when the drive vibration arms are excited in driving mode, the adjustment films are partly deleted by laser irradiation so that the detection current becomes 0.

Abstract: An acoustic wave device including: a substrate; a piezoelectric film formed on the substrate; an lower electrode provided on a first surface of the piezoelectric film; an upper electrode provided on a second surface of the piezoelectric film opposite to the first surface; and a mass loading film having a first pattern and a second pattern in a resonance portion in which the lower electrode and the upper electrode face each other through the piezoelectric film, the first pattern having portions and the second pattern having portions interlinking the portions of the first pattern.

Abstract: In a piezoelectric device, a lower covering layer, a piezoelectric material layer, a lower electrode layer, and an upper electrode layer, which define common layers, and an upper covering layer, which defines a specific layer, are laminated on a substrate. The piezoelectric material layer is sandwiched between a pair of electrodes. First to third vibration regions are provided in which the electrodes are superimposed with the piezoelectric material layer therebetween when viewed in a transparent manner in the direction in which the layers are laminated. The upper covering layer includes only a portion having with a first thickness in the first vibration region, includes a portion having the first thickness and a portion having a second thickness that is smaller than the first thickness in the second vibration region, and includes only a portion having the second thickness in the third vibration region.

Abstract: An acoustic wave device includes a main resonator and a sub resonator each having a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on an upper side of the piezoelectric film. A frequency control film is provided on an upper side of a resonance area in which the upper electrode and the lower electrode face each other in at least one of the main resonator and the sub resonator. The frequency control film has multiple convex patterns, and the convex patterns are arranged with a common pitch for spurious adjustment and with different areas in the main resonator and the sub resonator.

Abstract: Manufacturing a semiconductor structure including modifying a frequency of a Film Bulk Acoustic Resonator (FBAR) device though a vent hole of a sealing layer surrounding the FBAR device.

Abstract: A tunable resonator is provided that has a high Q for each resonate frequency. The tunable resonator is a MEMs tunable resonator wherein the tuner is affected by moving a moveable mass, associated with the resonating portion of the resonator, form a first position to a second position such that the moveable mass is held in the first position or second position by a detent rather than a constant electromagnet magnetic or electrostatic force applied thereon.

Abstract: A piezoelectric device includes first and second piezoelectric resonators each including a piezoelectric thin film, an upper electrode provided on one main surface of the piezoelectric thin film, and a lower electrode provided on another main surface of the piezoelectric thin film. In the piezoelectric resonators, portions in which the upper and lower electrodes are superposed on each other with the piezoelectric thin film therebetween define piezoelectric vibrating portions that are acoustically isolated from a substrate. The first and second piezoelectric resonators are connected in series or parallel between an input terminal and an output terminal such that polarization directions of corresponding portions of the piezoelectric thin film are opposite to each other when seen from the input terminal. The first piezoelectric resonator and the second piezoelectric resonator are arranged to have different resonant frequencies of a transverse vibration mode.

Abstract: A method of manufacturing an elastic wave device is provided with a lamination step of forming, on a substrate (1), a plurality of elastic wave devices, each of which includes a lower electrode (2), a piezoelectric film (3), and an upper electrode (4); a measuring step for measuring the operation frequency distribution of the elastic wave devices on the substrate (1); and an adjusting step for forming an adjusting region, in which the thickness of the elastic wave device is different from the thicknesses of other portions in a resonance portion of each elastic wave device, corresponding with the distribution of the operation frequencies. The adjusting region is formed so that the size of the area of the adjusting region of the resonator portion of each elastic wave device is different in accordance with the operation frequency distribution that is measured. Thus, the frequency characteristics of the elastic wave devices are easily adjusted by a small number of steps.

Abstract: A thin-film piezoelectric resonator including a substrate (6); a piezoelectric layer (2), a piezoelectric resonator stack (12) with a top electrode (10) and bottom electrode (8), and a cavity (4). The piezoelectric resonator stack (12) has a vibration region (40) where the top electrode and bottom electrode overlap in the thickness direction, and the vibration region comprises a first vibration region, second vibration region, and third vibration region. When seen from the thickness direction, the first vibration region is present at the outermost side, the third vibration region is present at the innermost side and does not contact the first vibration region, and the second vibration region is interposed between the first vibration region and third vibration region.

Abstract: In a quartz crystal unit, the unit comprising a quartz crystal resonator having an overall length less than 2.1 mm, and a base portion, and first and second vibrational arms, at least one groove being formed in at least one of opposite main surfaces of each of the first and second vibrational arms so that a width of the at least one groove is greater than or equal to a distance in the width direction of the at least one groove measured from an outer edge of the at least one groove to an outer edge of the corresponding one of the first and second vibrational arms and less than 0.07 mm, at least one metal film for adjusting an oscillation frequency of the quartz crystal resonator being disposed on at least one of the opposite main surfaces of each of the first and second vibrational arms.

Abstract: In one aspect of the invention, an acoustic wave device includes a substrate, an acoustic isolator formed in or on the substrate, a bottom electrode formed on the acoustic isolator, a piezoelectric layer formed on the bottom electrode, a top electrode formed on the piezoelectric layer, and boundary means such as a gasket surrounding one of the first and second electrodes whose perimeter is aligned inside the perimeter of the acoustic isolator. The gasket has a lateral side having a wall profile, a curve profile, a multi-step profile, a gradually variable profile, or a combination of them.

Abstract: A method and apparatus for determining phase sensitivity of an accelerometer based on an analysis of the harmonic components of the interference signal, which can estimate phase lags of an accelerometer through an analysis of the interference signal obtained using a single photo-detector when the accelerometer moves in sinusoidal motion with an initial phase of vibration. The method comprises the steps of obtaining an interference signal in a time domain generated from a signal reflected by an accelerometer and a fixed mirror using a single photo-detector; transforming the interference signal in the time domain into a signal in a frequency domain including a plurality of harmonic signals by Fourier transform; and determining the phase sensitivity of the accelerometer using initial phase of vibration displacement of the accelerometer, which is included in the interference signal in the frequency domain.

Abstract: A method of manufacturing a ladder filter including first and second resonators includes: forming a piezoelectric film on an entire surface of a substrate that has respective lower electrodes of the first and second resonator formed thereon, an conductive film on the piezoelectric film, and a second film on the conductive film; forming a pattern of the second film in a prescribed region in the second area; forming a first film on an entire surface of the substrate; etching the first film, forming a pattern of the first film, the second film and the conductive film in the second area, and forming a pattern of the first film and the conductive film in the first area, to form respective upper electrodes from the conductor film; and thereafter, etching the piezoelectric film to form respective patterns of the piezoelectric film in the first and second areas, respectively.

Abstract: An acoustic wave device includes piezoelectric thin-film resonators, each of which includes: a substrate; a piezoelectric thin-film on the substrate; an lower electrode provided on a first surface of the piezoelectric film; an upper electrode provided on a second surface of the piezoelectric film opposite to the first surface; and a first addition film that is provided in a resonance portion in which the lower electrode and the upper electrode face each other through the piezoelectric film and is located between the piezoelectric thin-film and the upper electrode, the first addition film having a shape different from that of the resonance portion.

Abstract: Disclosed herein is an apparatus. The apparatus includes a housing, a first piezo element, a second piezo element, and a mass. The first piezo element and the second piezo element are inside the housing. The mass is movably mounted inside the housing. The mass is configured to move inside the housing in response to a displacement of at least one of the first piezo element and the second piezo element. The mass is simultaneously in direct contact with the first piezo element and the second piezo element.

Abstract: An oscillator device comprises a resonator mass which is connected by a spring arrangement to a substrate and a feedback element for controlling oscillation of the resonator mass, which comprises a piezoresistive element connected between the resonator mass and the substrate. The invention provides an oscillator device in which the two parts (resonator and circuit to close the oscillation loop) are combined inside one single oscillator device, which can be a MEMS device.

Abstract: There is provided a method for testing a piezoelectric/electrostrictive actuator, wherein the displacement of a piezoelectric/electrostrictive actuator is estimated on the basis of the relations between one or more frequency characteristic values selected from the group consisting of the heights and areas of the peaks of the resonance waveforms and the difference of the maximum and minimum of the first order or first to higher orders of the resonance frequency characteristic values of the piezoelectric/electrostrictive actuator and the k-th order (k=1 to 4) of the first or first to higher orders of resonance frequencies. According to this piezoelectric/electrostrictive actuator testing method, a piezoelectric/electrostrictive actuator can be tested with high precision without actually driving the same as a product and without being accompanied by any disassembly/breakage.

Abstract: The present disclosure relates to a method of adjusting the resonance frequency of a vibrating element, comprising measuring the resonance frequency of the vibrating element, determining, using abacuses and as a function of the resonance frequency measured, a dimension and a position of at least one area of modified thickness to be formed on the vibrating element so that the resonance frequency thereof corresponds to a setpoint frequency, and forming on the vibrating element, an area of modified thickness of the determined dimension and position.

Abstract: In one general aspect, various embodiments are directed to an ultrasonic surgical instrument that comprises a transducer configured to produce a standing wave of vibrations along a longitudinal axis having a node and an anti-node at a predetermined frequency. In various embodiments, an ultrasonic blade extends along the longitudinal axis and is coupled to the transducer. In various embodiments, the ultrasonic blade includes a body having a proximal end and a distal end, wherein the distal end is movable relative to the longitudinal axis by the vibrations produced by the transducer. In one general aspect, various embodiments are directed to a method of assembling the transducer for the ultrasonic surgical instrument. In various embodiments, the method comprises selecting piezoelectric elements and arranging the piezoelectric elements relative to the node to minimize the difference in magnitude between the currents drawn by the piezoelectric elements.

Abstract: A vibrating element as an element on which a base part, a supporting part extending from the base part, and adjustment electrodes as mass adjustment parts are provided and a semiconductor substrate as a circuit element are provided, and the adjustment electrodes are placed in locations not overlapping with the semiconductor substrate in a plan view, the supporting part and the semiconductor substrate are connected, and thereby, the vibrating element is mounted on the semiconductor substrate.

Abstract: The piezoelectric devices allow outside-in adjustment of their vibration frequency. An exemplary piezoelectric device includes a tuning-fork type piezoelectric vibrating piece mounted inside a package. The vibrating piece has a base fabricated of a piezoelectric material, a pair of vibrating arms extending parallel from the base in a predetermined direction, and a frequency-adjustment unit situated on the distal ends of the vibrating arms. The package includes first metal films on the inner main surface thereof where an external laser beam can be irradiated. The frequency-adjustment unit includes a transparent region extending in a predetermined direction, allowing the laser beam, passing through the lid of the package, to be incident on second metal films by passing through the transparent regions. The laser beam also can be incident on first metal films without also being incident on the second metal films, by passing through the lid but not through the transparent regions.

Abstract: A vibrating element includes a vibrating arm for detection. An electrode is provided on the vibrating arm for detection. A wiring line is connected to the electrode. The wiring line is arranged on a piezoelectric body of a base portion. At least a part of the wiring line is an electrode for adjustment. The electrode for adjustment generates an electrical signal with an opposite phase to an output signal of leak vibration of the vibrating arm for detection.

Abstract: A vibration gyro-element includes a base portion, an excitation vibrating arm and a detection vibrating arm extending from the base portion, and a first adjustment vibrating arm and a second adjustment vibrating arm extending from the base portion and vibrating along with excitation vibration of the excitation vibrating arm, wherein an output signal of the first adjustment vibrating arm at least is out of phase with respect to an output signal of leakage vibration of the detection vibrating arm, and wherein an amplitude of the output signal of the first adjustment vibrating arm is larger than an amplitude of the output signal of the second adjustment vibrating arm.

Abstract: A method for forming a resonator including a resonant element, the resonant element being at least partly formed of a body at least partly formed of a first conductive material, the body including open cavities, this method including the steps of measuring the resonator frequency; and at least partially filling said cavities.

Abstract: A resonator comprises a bottom electrode layer (12), a top electrode layer (10) which defines a resonator body; and a piezoelectric layer (14) sandwiched between the top and bottom electrode layers. An external region (152) is provided around the outside of the periphery of the resonator body. The cutoff frequency of a first resonance mode of the external region (152) is matched to the cutoff frequency of a second, different, resonance mode of the resonator body. The invention provides a deliberate change (typically increase) in the cutoff frequency the resonance modes in the external region, so that one of the modes has a cutoff frequency close to the cutoff frequency of the fundamental mode of the resonator body.

Abstract: A bulk acoustic wave resonator has an adjustable resonance frequency. A piezoelectric element is provided having first and second electrodes. A switching element is provided in the form of a MEMS structure which is deformable between a first and second position. The switching element forms an additional electrode that is selectively disposed on top of, and in contact with, one of the first and second electrodes. This causes a total thickness of the electrode of the resonator to be changed resulting in a modification of the resonance frequency of the resonator.

Abstract: A bulk acoustic wave resonator desirably suppressing spurious modes includes a frame-like structure of mass loading contacting one electrode, wherein the frame-like structure is defined within inner and outer boundaries and wherein a central area extends through the resonator within an envelope of the inner boundary and a border region extends through the resonator within the inner and outer boundaries of the frame-like structure. A second electrode is positioned within the envelope and substantially missing from within the border region. A layer of piezoelectric material is embedded between the first and second electrodes. An active resonator area is substantially within the central area. The resonator structure is carried on a substrate and an acoustically reflective mirror having multiple and alternating layers of low and high acoustic impedance material.

Abstract: A tuning-fork type piezoelectric vibrating piece (20) is comprised of a base portion (23) comprising a piezoelectric material, a pair of vibrating arms (21) extends parallel from the base portion with a first thickness, a excitation electrode film (33, 34) formed on the vibrating arms, a pair of tuning portions (28) formed at the distal ends of the vibrating arms (21) with a second thickness which is less than the first thickness; and a metal film (18) formed on at least one surface o the tuning portion.

Abstract: Provided is a method for amplifying a frequency variation of a detected signal in a biosensor that is used for detecting a biomolecule by measuring a change in frequency of an oscillating signal, the change being caused by pressure a biomolecule applies to a piezoelectric substance. The method for amplifying a frequency variation of a detected signal comprises the steps of: (a) applying a sample to a probe being fixed to an upper portion of a substrate of the biosensor to allow a biomolecule in the sample to be bound to the probe; (b) applying protein tagged with a metal particle to the biosensor to allow the protein and the biomolecule to be bound with each other; and (c) applying a metal enhancer to the biosensor to allow the metal enhancer to be bound to the metal particle having been bound to the protein.

Abstract: In a method for manufacturing a piezoelectric oscillating circuit in thin film technology, wherein the oscillating circuit includes a predetermined natural frequency and a plurality of layers, first of all at least a first layer of the piezoelectric oscillating circuit is generated. Subsequently, by processing the first layer a frequency correction is performed. Subsequently, at least a second layer of the piezoelectric oscillating circuit is generated and processed for performing a second frequency correction.

Abstract: A fluid ejection module includes a die having a plurality of substantially identical fluid ejector units formed therein. Each fluid ejector unit includes a flow path formed therethrough, the flow path including a pumping chamber fluidically connected to a nozzle, and an actuator assembly including a membrane providing a wall of the pumping chamber and an actuator, the actuator assembly configured to eject fluid from a pumping chamber through an associated nozzle. The plurality of individually actuatable fluid ejector units includes a plurality of individually actuatable first fluid ejector units and at least one second fluid ejector unit, and the actuator assembly of the at least one second fluid ejector unit includes a material deposited on the actuator such that the actuator assembly of the at least one second fluid ejector unit is stiffer than the actuator assemblies of the first fluid ejector units.

Abstract: In an exemplary method for making crystal vibrating devices, four wafers are provided: a crystal wafer, a base wafer, a first-lid wafer, and a second-lid wafer. The crystal wafer defines multiple crystal vibrating pieces including respective frames and respective electrodes formed on both main surfaces thereof. The base wafer defines multiple base plates bondable to one main surface of respective frames. The first-lid wafer defines multiple first lids bondable to the other main surface of the respective frames. Each first lid defines a void registrable with respective electrodes. The second-lid wafer is sized similarly to and bondable to the first-lid wafer so as to sealably close the voids. In a first bonding step the crystal wafer is bonded to the base wafer and first-lid wafer. In a subsequent adjustment step the thickness of at least one electrode per each crystal vibrating piece is adjusted to adjust the vibrational frequency of the respective vibrating portion.

Abstract: A method of manufacturing a filter circuit including series and parallel coupled BAW resonators is given which compensates for frequency tolerances of the resonators which are due to the manufacturing process. The new method includes measuring a resonance frequency of at least one type of the BAW resonators produced on a wafer and defining a deviation from a desired frequency. A trimming layer is then deposited onto the entire wafer. At last, a thickness portion of the trimming layer is selectively removed, the portion being dependent on a location on the wafer and on the calculated deviation of the resonance frequency at this location.

Abstract: In a method for manufacturing a quartz crystal unit, a quartz crystal tuning fork resonator is formed by etching a quartz crystal wafer to form a quartz crystal tuning fork base, quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, and a groove having stepped portions in at least one of opposite main surfaces of each of the quartz crystal tuning fork tines. A first electrode is disposed on at least one of the stepped portions of each of the grooves and a second electrode is disposed on each of side surfaces of each of the quartz crystal tuning fork tines. A frequency of oscillation of the quartz crystal tuning fork resonator is adjusted at least twice and in different steps. The quartz crystal tuning fork resonator is then mounted in a case and an open end of the case is covered with a lid.