Abstract:
A crystal resonator comprises a first vibrating region provided on a crystal wafer, a second vibrating region provided on the crystal wafer, the second vibrating region having a different thickness and positive/negative orientation of the X-axis from those of the first vibrating region, and excitation electrodes which are provided respectively on the first vibrating region and the second vibrating region for causing the vibrating regions to vibrate independently. Frequencies that change by different amounts from each other relative to a temperature change can be retrieved from one vibrating region and the other vibrating region. Thus, based on an oscillating frequency of the vibrating region in which a clear frequency change occurs relative to the temperature, the oscillating frequency of the other vibrating region can be controlled. Thereby, increases in the complexity of the crystal oscillator can be suppressed.
Abstract:
Provided is a device capable of easily and accurately detecting a vibration period when, for example, an earthquake occurs. When a quartz-crystal plate bends upon application of a force, capacitance between a movable electrode provided at its tip portion and a fixed electrode provided on a vessel to face the movable electrode changes, so that an oscillation frequency of the quartz-crystal plate changes according to this capacitance. Therefore, when the vessel is vibrated, there appear a first state where the quartz-crystal plate ends to approach the fixed electrode and a second state where the quartz-crystal plate is in an original state or bends to be apart from the fixed electrode. Accordingly, an oscillation frequency corresponding to the first state and corresponding to the second state alternately appear, and therefore, it is possible to find the period (frequency) of the vibration.
Abstract:
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.
Abstract:
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.
Abstract:
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.
Abstract:
Provided is a piezoelectric resonator having high frequency stability and a sensing sensor using the piezoelectric resonator. A piezoelectric resonator has a first oscillation area which is provided in a piezoelectric piece and from which a first oscillation frequency is taken out. A second oscillation area which is provided in an area different from the first oscillation area via an elastic boundary area and from which a second oscillation frequency is taken out. Excitation electrodes are provided on one surface side and another surface side of the oscillation areas across the piezoelectric piece, and a frequency difference between the first oscillation frequency and the second oscillation frequency is not less than 0.2% nor greater than 2.2% of these oscillation frequencies.
Abstract:
To provide a sensing device that measures a substance to be sensed while letting a sample solution flow and has improved accuracy in detecting the substance to be sensed. The sensing device includes: a channel forming member 50 including an opposed surface opposed to an oscillation area on one surface side of a piezoelectric sensor via a gap to form a reaction channel in an area facing the one surface side; a liquid supply channel through which a liquid is supplied to the reaction channel and a liquid discharge channel through which a liquid is discharged from the reaction channel; oscillator circuits 30a, 30b oscillating the quartz-crystal piece; and a frequency measuring part 81 measuring oscillation frequencies of the oscillator circuits 30a, 30b, wherein a height of the reaction channel facing the oscillation area on the one surface side of the quartz-crystal sensor is 0.2 mm or less.
Abstract:
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° to 60°, 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.
Abstract:
To provide a sensing device using a piezoelectric sensor having an oscillation area for detection and an oscillation area for reference and capable of achieving a high measurement sensitivity by improving shapes of excitation electrodes. On a quartz-crystal piece 20a, there are provided strip-shaped left side area and right side area which are formed symmetrically to be separated from each other into left and right with respect to a center of a circle 53 being a contour of a planar shape of a reaction channel 52 and extend in a longitudinal direction in a parallel manner. Each of the areas is set to have a size in which both corner portions 100 on the left side of the left side area and both corner portions 100 on the right side of the right side area protrude to the outside of the circle 53, the corner portions 100 that protrude to the outside are cut to make the left side area and the right side area position inside of the circle 53, and an excitation electrode 21a for measurement and an excitation electrode 21b for reference are respectively formed on the right side area and the left side area.