Provided is an ultrasonic probe having an adjustable slew rate, the ultrasonic probe having minimal dimensions and circuit sizes. The ultrasonic probe includes: a transducer; a transmitting circuit; a correcting unit; and a distributing unit. The transmitting circuit includes a transducer driving unit and a current source. The transducer driving unit includes a current mirror of a low voltage transistor and a high voltage transistor. The high voltage transistor is connected to the transducer and the current source supplies an operating current to the low voltage transistor of the transducer driving unit. The correcting unit includes a transmission circuit driving unit replica, a bias unit, and an observing unit. The distributing unit transfers a signal to a current source of the transmitting circuit so that the same current value as the current value extracted by the observing unit flows.

Provided is an ultrasonic probe having an adjustable slew rate, the ultrasonic probe having minimal dimensions and circuit sizes. The ultrasonic probe includes: a transducer; a transmitting circuit; a correcting unit; and a distributing unit. The transmitting circuit includes a transducer driving unit and a current source. The transducer driving unit includes a current mirror of a low voltage transistor and a high voltage transistor. The high voltage transistor is connected to the transducer and the current source supplies an operating current to the low voltage transistor of the transducer driving unit. The correcting unit includes a transmission circuit driving unit replica, a bias unit, and an observing unit. The distributing unit transfers a signal to a current source of the transmitting circuit so that the same current value as the current value extracted by the observing unit flows.

A process for determining the quality of a laser weld-seam, whereby a welded plate and a geometrically equivalent non-welded plate are subjected to a physical impact to generate a natural vibration frequency. The natural vibration frequency of the welded plate and the non-welded plate is then measured with an accelerometer and compared. The uniformity of the weld is then determined by the similarity between the natural vibration frequency of the welded plate and the geometrically equivalent non-welded plate.

A process for determining the quality of a laser weld-seam, whereby a welded plate and a geometrically equivalent non-welded plate are subjected to a physical impact to generate a natural vibration frequency. The natural vibration frequency of the welded plate and the non-welded plate is then measured with an accelerometer and compared. The uniformity of the weld is then determined by the similarity between the natural vibration frequency of the welded plate and the geometrically equivalent non-welded plate.

Disclosed sensors can include at least one resonator (in some embodiments, at least two resonators) and various other structures that may be formed in association with the resonators. The at least one resonator in embodiments can include a bottom electrode, a piezoelectric layer, and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode.

Disclosed sensors can include at least one resonator (in some embodiments, at least two resonators) and various other structures that may be formed in association with the resonators. The at least one resonator in embodiments can include a bottom electrode, a piezoelectric layer, and a top electrode, wherein the piezoelectric layer is positioned between the bottom electrode and the top electrode.

A method in which an acoustic sensor disposed in a polishing apparatus can be accurately calibrated is disclosed. In this method, polishing sounds of a substrate are acquired using an acoustic sensor; and then at least two distinctive sounds, having distinctive frequencies respectively, are selected from the acquired polishing sounds. Further, the at least two distinctive sounds are output from a sound source coupled to any of a polishing table, the acoustic sensor, and a substrate holder to cause the at least two distinctive sounds to be input to the acoustic sensor. Next, output values of the acoustic sensor are calibrated, such that the output values of the acoustic sensor relative to the at least two distinctive sounds come within an allowable range.

A method in which an acoustic sensor disposed in a polishing apparatus can be accurately calibrated is disclosed. In this method, polishing sounds of a substrate are acquired using an acoustic sensor; and then at least two distinctive sounds, having distinctive frequencies respectively, are selected from the acquired polishing sounds. Further, the at least two distinctive sounds are output from a sound source coupled to any of a polishing table, the acoustic sensor, and a substrate holder to cause the at least two distinctive sounds to be input to the acoustic sensor. Next, output values of the acoustic sensor are calibrated, such that the output values of the acoustic sensor relative to the at least two distinctive sounds come within an allowable range.

A method for calibrating an ultrasonic sensor including a transducer, a reflector spaced a known distance from the transducer, and a memory. A water bath is heated to approximately fifty centigrade and the ultrasonic sensor is at least partially submerged in the water bath. When submerged, an ultrasonic wave is transmitted through a portion of the water bath from the transducer. The ultrasonic wave is transmitted toward the reflector and a reflected ultrasonic wave is received back at the transducer. A time of flight of the ultrasonic wave is measured. A calibration coefficient is determined based on the time of flight of the ultrasonic wave and an expected time of flight of the ultrasonic wave. The calibration coefficient is loaded into the memory of the ultrasonic sensor.

A method for calibrating an ultrasonic sensor including a transducer, a reflector spaced a known distance from the transducer, and a memory. A water bath is heated to approximately fifty centigrade and the ultrasonic sensor is at least partially submerged in the water bath. When submerged, an ultrasonic wave is transmitted through a portion of the water bath from the transducer. The ultrasonic wave is transmitted toward the reflector and a reflected ultrasonic wave is received back at the transducer. A time of flight of the ultrasonic wave is measured. A calibration coefficient is determined based on the time of flight of the ultrasonic wave and an expected time of flight of the ultrasonic wave. The calibration coefficient is loaded into the memory of the ultrasonic sensor.