In a crystal oscillator, a crystal resonator and an IC chip are hermetically sealed in a package. The crystal resonator includes: a crystal resonator plate including a first excitation electrode formed on a first main surface, and a second excitation electrode, which makes a pair with the first excitation electrode, formed on a second main surface; a first sealing member covering the first excitation electrode of the crystal resonator plate; and a second sealing member covering the second excitation electrode of the crystal resonator plate. A vibrating part including the first excitation electrode and the second excitation electrode of the crystal resonator plate is hermetically sealed by bonding the first sealing member to the crystal resonator plate, and the second sealing member to the crystal resonator plate.

A crystal vibrator that includes a crystal vibration element having a crystal piece and a pair of electrodes that face each other with the crystal piece interposed therebetween; and a holder that accommodates the crystal vibration element. At least one electrode of the pair of electrodes includes an upper layer containing gold and a lower layer between the crystal piece and the upper layer and containing chromium. A surface of the at least one electrode contains a plurality of crystal grains composed of gold and a chromium compound along grain boundaries between the plurality of crystal grains. An area percentage of the plurality of crystal grains is equal to or more than 35% and equal to or less than 60% when the surface of the at least one electrode is viewed in a plan view thereof.

A crystal vibrator that includes a crystal vibration element having a crystal piece and a pair of electrodes that face each other with the crystal piece interposed therebetween; and a holder that accommodates the crystal vibration element. At least one electrode of the pair of electrodes includes an upper layer containing gold and a lower layer between the crystal piece and the upper layer and containing chromium. A surface of the at least one electrode contains a plurality of crystal grains composed of gold and a chromium compound along grain boundaries between the plurality of crystal grains. An area percentage of the plurality of crystal grains is equal to or more than 35% and equal to or less than 60% when the surface of the at least one electrode is viewed in a plan view thereof.

An acoustic wave element which can be reduced in size and produced relatively easily, practically used without using harmful substances, and can suppress a surface acoustic wave propagation loss, which has an excellent temperature coefficient of frequency and a velocity dispersion characteristic, and with which an increase in the reflection coefficient of interdigital transducers can be suppressed, and a method for manufacturing the acoustic wave element are provided. The acoustic wave element includes a pair of electrodes provided on both surfaces of a piezoelectric substrate, and a dielectric film provided on a first surface of the piezoelectric substrate so as to cover the electrode. The acoustic wave element alternatively includes interdigital transducers provided on a first surface of the piezoelectric substrate, and a dielectric film provided on the interdigital transducers, a gap between the interdigital transducers, and/or a second surface of the piezoelectric substrate.

An acoustic wave element which can be reduced in size and produced relatively easily, practically used without using harmful substances, and can suppress a surface acoustic wave propagation loss, which has an excellent temperature coefficient of frequency and a velocity dispersion characteristic, and with which an increase in the reflection coefficient of interdigital transducers can be suppressed, and a method for manufacturing the acoustic wave element are provided. The acoustic wave element includes a pair of electrodes provided on both surfaces of a piezoelectric substrate, and a dielectric film provided on a first surface of the piezoelectric substrate so as to cover the electrode. The acoustic wave element alternatively includes interdigital transducers provided on a first surface of the piezoelectric substrate, and a dielectric film provided on the interdigital transducers, a gap between the interdigital transducers, and/or a second surface of the piezoelectric substrate.

An oscillator includes a first resonator element, a first package that accommodates the first resonator element, a relay substrate on which the first package is mounted, a heater element that is attached to the first package or the relay substrate, a second package that accommodates the first package, and a heat insulating member that is provided at least between the second package and the relay substrate or between the relay substrate and the first package.

An oscillator includes a first resonator element, a first package that accommodates the first resonator element, a relay substrate on which the first package is mounted, a heater element that is attached to the first package or the relay substrate, a second package that accommodates the first package, and a heat insulating member that is provided at least between the second package and the relay substrate or between the relay substrate and the first package.

A resonator device includes an element substrate including a frame part having a first surface and a second surface in a front-back relationship with each other, and a resonator element which is coupled to the frame part, and is arranged inside the frame part, a first substrate which is arranged at the first surface side, and has a third surface faced to the first surface, a first bonding layer which is arranged between the element substrate and the first substrate, and which is configured to bond the first surface and the third surface to each other, a second substrate which is arranged at the second surface side, and has a fourth surface faced to the second surface, a second bonding layer which is arranged between the element substrate and the second substrate, and which is configured to bond the second surface and the fourth surface to each other, a housing part which is surrounded by the frame part, the first substrate, and the second substrate, and which houses the resonator element, and a getter layer which is arranged on the fourth surface, exposed to the housing part, and has a gas adsorptive property.

A resonator device includes an element substrate including a frame part having a first surface and a second surface in a front-back relationship with each other, and a resonator element which is coupled to the frame part, and is arranged inside the frame part, a first substrate which is arranged at the first surface side, and has a third surface faced to the first surface, a first bonding layer which is arranged between the element substrate and the first substrate, and which is configured to bond the first surface and the third surface to each other, a second substrate which is arranged at the second surface side, and has a fourth surface faced to the second surface, a second bonding layer which is arranged between the element substrate and the second substrate, and which is configured to bond the second surface and the fourth surface to each other, a housing part which is surrounded by the frame part, the first substrate, and the second substrate, and which houses the resonator element, and a getter layer which is arranged on the fourth surface, exposed to the housing part, and has a gas adsorptive property.

A quartz crystal resonator unit includes a quartz crystal resonator that includes a quartz crystal blank. A pair of excitation electrodes are disposed on opposed main surfaces of the quartz crystal blank so as to face each other. A pair of connection electrodes are electrically connected to respective ones of the pair of excitation electrodes. A base member has a surface on which the quartz crystal resonator is mounted. A lid member is joined to the surface of the base member via a joining member. The quartz crystal resonator is accommodated in an inner space defined by the lid member and the base member on the surface of the base member. Parts of the joining member that cover protruding portions are in contact with a side wall of the lid member so as to restrain movement of the lid member when seen in a plan view in a direction normal to the surface of the base member.