Abstract: A capacitive microfabricated ultrasonic transducer with control of elevation phase through alternating bias polarity is disclosed. Such control of elevation phase results in simple ultrasonic probes with excellent slice thickness attributes. Furthermore, tight spatial variation of phase results in an effective way to achieve transmit aperture and apodization control. Further still, such capacitive microfabricated ultrasonic transducers can achieve elevation focus without the need of a lossy mechanical lens.

Abstract: The present invention provides a method of packaging surface microfabricated transducers such that electrical connections, protection, and relevant environmental exposure are realized prior to their separation into discrete components. The packaging method also isolates elements of array transducers. Post processing of wafers consisting of transducers only on the top few microns of the wafer surface can be used to create a wafer scale packaging solution. By spinning or otherwise depositing polymeric and metallic thin and thick films, and by lithographically defining apertures and patterns on such films, transducers can be fully packaged prior to the final dicing steps that would separate the packaged transducers from each other. In the case of microfabricated ultrasonic transducers, such packaging layers can also enable flexible transducers and eliminate or curtail the acoustic cross-coupling that can occur between array elements.

Abstract: The present invention provides a microfabricated acoustic transducer with suppressed substrate modes. The modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or by applying a judiciously designed damping material on the backside of the transducer substrate.

Abstract: The present invention provides a method of packaging surface microfabricated transducers such that electrical connections, protection, and relevant environmental exposure are realized prior to their separation into discrete components. The packaging method also isolates elements of array transducers. Post processing of wafers consisting of transducers only on the top few microns of the wafer surface can be used to create a wafer scale packaging solution. By spinning or otherwise depositing polymeric and metallic thin and thick films, and by lithographically defining apertures and patterns on such films, transducers can be fully packaged prior to the final dicing steps that would separate the packaged transducers from each other. In the case of microfabricated ultrasonic transducers, such packaging layers can also enable flexible transducers and eliminate or curtail the acoustic cross-coupling that can occur between array elements.

Abstract: An electrostatic transducer circuit and method of tuning the same, in which a balancing inductance is inserted into the electrostatic transducer circuit is described. The electrostatic transducer circuit generally includes transmit circuitry, receive circuitry and a capacitive electrostatic transducer. The balancing inductance is tuned to counteract the negative reactance of the capacitive electrostatic transducer at a desired operating frequency during the transmit mode. The balancing inductance is inserted into the transmit circuitry and is then isolated from the remaining parts of the electrostatic transducer circuit. Isolation is achieved by switching the electrostatic transducer circuit between transmit and receive modes of operation. Further, a receive circuit balancing reactance can also be included. The method provides a balancing inductance that is used to counteract negative reactance of the capacitive electrostatic transducer at a desired operating frequency during transmit mode.

Abstract: A microfabricated acoustic transducer with suppressed substrate modes includes a diaphragm containing an upper electrode suspended above a substrate containing a lower electrode; the substrate may or may not contain electronic circuits. The substrate modes are suppressed by either thinning the substrate such that a longitudinal ringing mode occurs outside of the frequency band of interest or applying a judiciously designed damping material that absorbs acoustic energy from the substrate on the backside of the transducer substrate, or by both thinning the substrate and applying the damping material. The damping material has an acoustic impedance that matches the acoustic impedance of the substrate and is lossy.

Abstract: The present invention provides an acoustic transducer, or an array of such transducers, formed on a single integrated circuit chip, and a method of making the same, in which there is included an array of acoustic transducers, each capable of detecting an acoustic signal and generating a transducer signal, and including a first and second electrode with a void region disposed between the first and second electrode, and at least one signal line associated with one of the first and second electrodes. Disposed below the array of acoustic transducers is a plurality of amplifiers and other circuit components, such that each of the plurality of amplifiers is coupled to one of the signal lines associated with one of the acoustic transducers and is capable of amplifying the associated transducer signal to obtain an amplified transducer signal on an amplifier output signal line.

Abstract: The present invention provides an acoustic transducer, or an array of such transducers, formed on a single integrated circuit chip, and a method of making the same, in which there is included an array of acoustic transducers, each capable of detecting an acoustic signal and generating a transducer signal, and including a first and second electrode with a void region disposed between the first and second electrode, and at least one signal line associated with one of the first and second electrodes. Disposed below the array of acoustic transducers is a plurality of amplifiers and other circuit components, such that each of the plurality of amplifiers is coupled to one of the signal lines associated with one of the acoustic transducers and is capable of amplifying the associated transducer signal to obtain an amplified transducer signal on an amplifier output signal line.

Abstract: The present invention provides an ultrasonic resonant cavity droplet ejector with localized excitation and a method for making the same. In a resonant cavity with an ultrasonic transducer acting as one of the cavity walls, the energy input from the transducer coupled with the gain of the resonant cavity causes a droplet to be ejected from a nozzle in the cavity wall. In addition, a refill channel can be introduced such that the cavity can be refilled without affecting cavity gain. Arrays of such locally excitable ejector cavities are useful in numerous applications, including, among others, ink-jet printing, DNA chip printing, and fuel injectors.

Abstract: The present invention provides an transducer and a method of making the same. The transducer is comprised of a plurality of transducer cells, and conductive interconnects between the cells. Each transducer cell contains a bottom electrode formed on a layer of insulator material, a lower insulating film portion formed over the bottom electrode, a middle insulating film portion that includes an air/vacuum void region, and an upper insulating film portion that includes a top electrode formed within a portion of the upper insulating film portion. A first layer of interconnects electrically connect the bottom electrodes of each transducer cell and a second layer of interconnects electrically connect the top electrodes of each transducer cell. The top and bottom layers of interconnects are patterned to avoid overlap between them, thus reducing the parasitic capacitance.

Abstract: The present invention provides an transducer and a method of making the same. The transducer is comprised of a plurality of transducer cells, and conductive interconnects between the cells. Each transducer cell contains a bottom electrode formed on a layer of insulator material, a lower insulating film portion formed over the bottom electrode, a middle insulating film portion that includes an air/vacuum void region, and an upper insulating film portion that includes a top electrode formed within a portion of the upper insulating film portion. A first layer of interconnects electrically connect the bottom electrodes of each transducer cell and a second layer of interconnects electrically connect the top electrodes of each transducer cell. The top and bottom layers of interconnects are patterned to avoid overlap between them, thus reducing the parasitic capacitance.

Abstract: The present invention provides an acoustic transducer, or an array of such transducers, formed on a single integrated circuit chip, and a method of making the same, in which there is included an array of acoustic transducers, each capable of detecting an acoustic signal and generating a transducer signal, and including a first and second electrode with a void region disposed between the first and second electrode, and at least one signal line associated with one of the first and second electrodes. Disposed below the array of acoustic transducers is a plurality of amplifiers and other circuit components, such that each of the plurality of amplifiers is coupled to one of the signal lines associated with one of the acoustic transducers and is capable of amplifying the associated transducer signal to obtain an amplified transducer signal on an amplifier output signal line.