Nihon Dempa Kogyo Co., Ltd.

Hiroki Iwai

Ryoichi Ichikawa

Mitsuaki Koyama

Takeru Mutoh

Yoshiaki Amano

Shingo Kawanishi

Masahiro Yoshimatsu

Yu Iwai

Hiroshi Uehara

Shunsuke Ueno

A technique for detecting external force applied to a piezoelectric plate is provided. A crystal plate is cantilever-supported in a container. Excitation electrodes are formed on an upper face and lower face, respectively, of the crystal plate. A movable electrode is formed on the lower face side. A fixed electrode is provided on a bottom portion of the container facing the movable electrode. The excitation electrode on the upper face side and the fixed electrode are connected to an oscillation circuit. When the crystal plate bends by external force applied, capacitance between. A direction of the movable electrode along a length direction of the crystal plate is set to 30&#xb0; to 60&#xb0;, relative to a face orthogonal to an intended direction of the external force. The movable electrode and fixed electrode changes, and this capacitance change and a deformation of the crystal circuit.

External force detecting method and external force detecting device

A device is provided for a detecting external force applied to piezoelectric piece. A crystal piece is cantilever-supported in a container. Excitation electrodes are formed on an upper face and lower face, respectively. A movable electrode, connected via a lead-out electrode to the excitation electrode, is formed on the lower face side at a front end of the crystal piece. A fixed electrode is provided on a bottom portion of the container to face this movable electrode. The excitation electrode on the upper face side and the fixed electrode are connected to an oscillation circuit. When the crystal piece bends in response to an applied external force, capacitance between the movable electrode and fixed electrode, changes. This capacitance change results in a corresponding change in oscillation frequency of the crystal piece.

External force detecting device and external force detecting sensor

A piezoelectric device including a tuning-fork piezoelectric vibrating element having a base and a pair of vibrating arms positioned parallel to each other and extending from the base at right angles. The piezoelectric device further including a pair of support arms extending from the base positioned parallel to each other and in the same direction as the vibrating arms. A package is included having a lid and a housing recess sealed by the lid wherein the tuning-fork piezoelectric vibrating element is housed. A pair of supports are provided on a bottom face of the housing recess for fixing the tuning-fork piezoelectric vibrating element by the support arms. A clearance groove is formed in the bottom face of the housing access to prevent the tuning-fork piezoelectric vibrating element from colliding against the bottom face of the housing recess.

Tuning fork piezoelectric vibrator with clearance groove formed on the base side of the package

An acceleration measuring apparatus that can easily detect acceleration with high accuracy is provided. In the apparatus, positional displacement of a swingable pendulum member is detected, feedback control is performed to maintain the pendulum member in a stationary state using an actuator, and acceleration is measured by measuring the output of the actuator at this time. A movable electrode is provided to the pendulum member, and a loop is formed in which a fixed electrode provided to oppose the movable electrode, and an oscillating circuit, a crystal unit, and the movable electrode are electrically connected in series. By measuring an oscillating frequency of the oscillating circuit at this time, a change in the size of a variable capacitance formed between the movable electrode and the fixed electrode is detected, and thereby the positional displacement of the pendulum member is detected.

Acceleration measuring apparatus

In an external force detection apparatus, a crystal plate is cantilevered within a container. Excitation electrodes are formed on the top surface and the bottom surface of the crystal plate. A movable electrode is formed on a distal end on the bottom surface of the crystal plate and is connected to the excitation electrode on the bottom surface via an extraction electrode. A fixed electrode is provided on the bottom of the container to oppose the movable electrode. The excitation electrode on the top surface and the fixed electrode are connected to an oscillating circuit. When an external force acts on the crystal plate to bend it, the capacitance between the movable electrode and the fixed electrode changes, and this capacitance change is captured as a change in the oscillating frequency of the crystal plate.

External force detection apparatus and external force detection sensor

An exemplary tuning-fork type piezoelectric vibrating piece has a rectangular base having upper and lower main surfaces and a pair of vibrating arms extending longitudinally from the base. The vibrating arms also have the upper and lower main surfaces. Each main surface of each vibrating arm defines a respective vibrating-arm groove extending longitudinally into the base. Each main surface of the base has at least one respective step-side surface situated outboard, in an X-axis direction, of each vibrating-arm groove. Each step-side surface is parallel with the respective vibrating-arm groove. A first electrode is situated on the vibrating-arm grooves of the first vibrating arm and on the at least one respective step-side surface on each main surface. A second electrode is situated on the vibrating-arm grooves of the second vibrating arm and on the at least one respective step-side surface on each main surface. The first and second electrodes are energized with different electrical polarities.

Piezoelectric vibrating pieces and associated devices exhibiting enhanced electrical field

Piezoelectric vibrating pieces are disclosed that include a base, a pair of vibrating arms, and a pair of supporting arms. The base is fabricated of piezoelectric material. The vibrating arms extend straight from the base in a designated longitudinal direction and having a first thickness. A respective supporting arm extends straight from the base and outboard of each vibrating arm in the designated longitudinal direction. Each supporting arm includes at least a respective second region that has second thickness different from the first thickness.

Piezoelectric vibrating pieces and corresponding devices exhibiting reduced vibration leakage

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

Tuning-fork type piezoelectric vibrating piece with enhanced frequency adjustment and piezoelectric device incorporating same

An object of the invention is to provide a surface mounted resonator that improves impact resistance by the shape of a mounting terminal provided on an outside bottom face of a stacked resonator. A surface mounted crystal resonator is provided with a plurality of mounting terminals electrically connected to a hermetically sealed crystal piece at both ends of an outside bottom face having a rectangular shape long in the lengthwise direction, the mounting terminals having the same external dimensions with a total dimension of the mounting terminals in a lengthwise direction of the outside bottom face being 70% or more [but less than 100%] of a dimension in the lengthwise direction of the outside bottom face. Respective facing sides of the mounting terminals facing each other in a central area of the outside bottom face are formed curved in a convex shape such that a curvature thereof decreases gradually.

Surface mounted crystal resonator

An exemplary tuning-fork type piezoelectric vibrating piece has at least a pair of vibrating arms extending from one end of a base portion in a certain longitudinal direction (e.g., Y-direction). Supporting arms extend from respective side edges of the base, outboard of the vibrating arms in the certain direction. The supporting arms have respective mounting regions near their distal tips. Each supporting arm progressively narrows from its proximal end, coupled to the respective side edge of the base, to its respective mounting region. The progressive narrowing can be via one or more constrictions along the length of the supporting arm.

Piezoelectric vibrating devices having bisymmetric vibrating arms and supporting arms, and devices comprising same

Piezoelectric frames are disclosed that include a tuning-fork type piezoelectric vibrating portion having a pair of vibrating arms extending from a base portion in a first direction (Y-direction). The vibrating arms have a first width W. A respective excitation electrode is formed on each vibrating arm. Supporting arms extend from the base portion in the first direction, outboard of respective vibrating arms. The supporting arms have a second width W. A respective connecting arm extends from each supporting arm in a second direction that crosses the first direction. An outer frame connects to the connecting arms, has a side extending in the first direction with a third width W, and has another side extending in the second direction with a fourth width W. The second width Wis 1.4 times smaller than the first width W

Piezoelectric frames and piezoelectric devices comprising same

An exemplary piezoelectric vibrating device has a lid plate, a chip plate including a tuning-fork type vibrating piece surrounded by an outer frame, and a package base arranged where the chip plate is sandwiched between the lid plate and package base, and the three layers are bonded together. The tuning-fork type piezoelectric vibrating piece is connected to the outer frame by supporting arms. A base-movement buffer having a predetermined height in the X-direction extends from the inner edge surface of the outer frame toward a side edge of the base. The base-movement buffer has a height in the X-direction that is proportional to the length from the base-movement buffer to a point at which the tuning-fork type piezoelectric vibrating piece is coupled to the outer frame.

Piezoelectric devices having improved impact resistance

Piezoelectric frames are disclosed that include a tuning-fork type piezoelectric vibrating piece. The vibrating piece has at least a pair of vibrating arms that extend in a longitudinal direction (e.g., Y-direction) from a first end edge of a piezoelectric base, and at least one excitation electrode on the pair of vibrating arms. Respective supporting arms extend in the longitudinal direction, outboard of each vibrating arm. The vibrating piece is surrounded by and attached to a frame portion also made of piezoelectric material. A pair of connecting portions connects the supporting arms to the frame portion. The connecting portions extend from respective supporting arms to the frame portion in a direction that intersects the longitudinal direction. The connecting portions are connected to the frame portion at designated locations that are more than 50% of the designated length of the vibrating piece from the second end edge of the base.

Piezoelectric vibrating pieces are disclosed made of a piezoelectric material to be mounted in a package. A representative piece includes a base formed of a piezoelectric material, having first and second ends, extending between the ends in a length direction, and having a designated width. The piece includes at least a pair of vibrating arms extending in the length direction from one end of the base, and a pair of supporting arms extending partially in a width direction from between the first and second ends of the base. The supporting arms further extend in the length direction outboard of the base and vibrating arms, and include an adhesive region at the tips of the supporting arms. The adhesive regions are used for mounting the piece to a package. Whereas the tips of the supporting arms do not extend beyond the tips of the vibrating arms, the axial length of supporting arms is greater than the length of the vibrating arms.

Growing community of inventors

Saitama, Japan

Hiroki Iwai