Request Expert

He is expert in the design of ultrasonic transducers (MHz range medical/industrial, acoustic or vibration sensor/actuators). Typical applications are, medical ultrasound imaging probes, medical diagnostic sensors, medical ablation tools by high energy focused ultrasound, eye surgery sensors, eye motion sensors, dental imaging, human skin stress sensors, air ultrasound for distance measurement, liquid flow meters, accelerometers etc.
He has particular expertise in the use of theoretical models and experiments to develop new design principle for design of transducers and sensors. These include new impedance matching layers for ultrasonic probes, including unique mass-spring matching layers (invented) using polymer/metal -- much thinner than conventional quarter wavelength -- providing wide bandwidth with feasibility of mass production.

He is also an expert in the new design of ultrasonic probe by use of backing absorbers using polymer metal multilayer (invented) replacing conventional metal powder/binder combination, with feature of theoretical design, reproducible and mass production feasible. His expertise areas include the design of complex multilayer transducers with simulation programs for which he wrote 700 programs from his own theoretical derivation -- not borrowing a published model. Therefore he understands acoustic transducers from deep physics. He can modify or simplify acoustic transducers with great freedom, potentially leading to many creative ideas.

He is an expert in pioneered device applications of piezoelectric polymer PVDF film. He has worked in this field for over 40 years. These device applications include cylindrical film air ultrasonic transducers in the 40-80 kHz range, which are commercially being sold as input devices of hand written patterns.
Expert's inventions also include a large area corrugated PVDF ultrasonic air transducer providing very large acoustic pressure, used as ultrasonic range finder.
Another field is multilayer sensor/actuator for stress-strain detection or vibrator or acoustic radiator. He wrote theoretical models/programs of multilayer sensor/actuator and is a design expert of arbitrarily complicated layer structure. He has also pioneered theories and experiments of air flow generation from PVDF bimorph vibrator fan.

Expert's specialty areas include the design of electrical matching networks for ultrasonic transducer enhancing sensitivity (x10) and widening or tailoring bandwidth. Generally it is known that matching network improves performance. However, when a single transducer is used as transmitter and receiver for reflection echo detection, usually a single matching network is added to the transducer and TR switch is used for switching from transmitter to receiver.
The expert's unique, novel method is (1) measurement of electrical impedance of the transducer, (2) Design of two separated networks with most suitable performance for transmitter and receiver respectively, (3) These networks are combined by TR switch for single transducer without reduction or interference of performance of both networks, so that frequency response can be synthesized. All these networks and transducer performance are designed by simulation programs. The simulation programs include connection cable effect (transmission line), all of which were derived from theoretical analysis.

The expert's special design capabilities include application of lithium niobate (LiNbO3 ) vibrator for online detection of density and viscosity, important field of automobile sensors, which include theoretical analysis of density/viscosity effect to vibrator. Almost all designers of this field use equivalent circuit model for liquid parameter measurement but transducer design is not included. The expert's design uses physics based theory and material and structural parameters of transducer, with transducer design, such as feature of crystal cut directions, temperature coefficient of elasticity leading to temperature dependence of resonance, device length/width effect, etc.

The expert's specialties includes analysis of acoustic beam forming for ultrasonic wave. When multiple radiation sources are used, the beam direction and intensity distribution are controlled by phase of each radiation source. The expert have simulation program predicting distribution of near-field region and far filed, which was build by himself from theoretical principle of acoustic radiation. Therefore, complicated near field patterns can be predicted and combined with design of ultrasonic transducers to predict system performance of imaging equipment.

The expert has many measurement equipment and components, which can be used for measurement of acoustic velocity of materials, input impedance of ultrasonic transducer, flow velocity from time of flight, observation of deflection or displacement with microscope or video camera, determination of acoustic parameters of thin film from influence to transducer performance from parameter fitting combined with simulation program.
He has great numbers of piezoelectric materials and components, various thickness/size of PZT, PVDF, LiNbO3, other polymer films and finished devices, semiconductor lasers / LED and optical detectors, which can be used for measurement of various parameters depends on specific need.

The expert has 50 years experience of material processing experienced at several laboratories. He is proficient for manipulation of microns to submillimeter scale devices and fabrication under microscope, which include layer to layer epoxying, lead wire attachment by conductive paint/epoxy, microscope inspection of connection failure or shorting or observation of surface condition. He does poling of piezoelectric materials. He also does machine work for building his own experimental set up, device fabrication or device holder and he has table top lathe, grinder, drill, high speed rotation tools, all for small devices fabrication.

The expert builds interface circuits necessary for measurement of the devices under test or unique device operation combined with the specific circuit. This capability makes it possible to enhance measurement range or accuracy or better signal to noise ratio, or some unique operation of special devices combine with unique circuit.

If problems, requirements or specifications on new product development are provided, the solution may be by new ideas, and theoretical prediction will be proposed and experimental confirmation work will be done. Great number of measurement equipment/materials/tools/transducer/sensors are readily available for investigations, all of which were used during his 30 years research/development efforts, and therefore experimental investigations can be efficient and quickly or effectively done.