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Yanggu, South Korea

Yang J.,Seoul National University | Lee S.,IBULe Photonics Co. | Kim J.,Seoul National University
Electronics Letters

The optimal capacitive load condition is derived for a passive bridge rectifier to harvest the maximum amount of energy when a piezoelectric generator (PG) receives a single vibration pulse (e.g. a button press). When the PG is modelled as a current pulse generator with an internal shunt capacitance (C P), it is shown that an ideal bridge rectifier collects the maximum energy when its output capacitance is set to 3·CP. The impacts of the nonzero turn-on voltage and on-resistance of the diodes are also discussed. The experimental results with a 300 mm2 lead magnesium niobate-lead titanate PG and a Schottky-bridge rectifier with 0.22 V turn-on voltage demonstrate that the maximum energy transfer occurs at a capacitance ratio of 3.3, collecting 117 μJ from a single button press. © The Institution of Engineering and Technology 2014. Source

Yu J.,University of Pittsburgh | Jung Y.,University of Pittsburgh | Kang J.,Sogang University | Lee S.G.,IBULe Photonics Co. | And 4 more authors.
IEEE International Ultrasonics Symposium, IUS

A large portion of near infrared (NIR) laser energy is lost at the skin surfaces by reflection, for example 30% of the incident energy reflects off with incident angle of 20°. Retrieving the reflected light and redirecting it onto the skin surfaces will increase the effective excitation energy, resulting in an increased photoacoustic (PA) signal for the same light source without increasing power. Increased uniformity of light distribution on the skin is also expected due to multiple random light reflection inside a light retrieving and reflection device. In this study, we fabricated a relatively simple, but effective light illumination improvement device, called light catcher, and integrated it into a compact high frequency ultrasound transducer for small animal imaging. Using chicken breast tissues and a mouse cancer model, feasibility of the light catcher for PA imaging was demonstrated. When using the light catcher, PA signal intensity was increased by 33% (0.44 vs. 0.30) and 28% (0.57 vs. 0.41), and corresponding CNR was improved by 22% (2.66 vs. 2.18) and 23% (1.96 vs. 1.52) compared to without the light catcher for in vitro and in vivo study, respectively. This device might allow deep tissue PA imaging with improved CNR using the same laser power. © 2014 IEEE. Source

Yu P.,InfraTec GmbH | Ji Y.,InfraTec GmbH | Neumann N.,InfraTec GmbH | Lee S.-G.,IBULe Photonics Co. | And 2 more authors.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control

The suitability for use in pyroelectric detectors of single-crystalline doped and undoped lead indium niobate- lead magnesium niobate-lead titanate was tested and compared with high-quality Mn-doped lead magnesium niobate- lead titanate and standard lithium tantalate. Pyroelectric and dielectric measurements confirmed an increased processing and operating temperature range because of the higher phase transitions of lead indium niobate-lead magnesium niobate-lead titanate. Pyroelectric coefficients of 705 to 770 μC/m 2K were obtained with doped and undoped lead indium niobate-lead magnesium niobate-lead titanate, which are about 70% to 80% of the pyroelectric coefficient of lead magnesium niobate-lead titanate but 4 times higher than standard lithium tantalate. Manganese doping has been proved as a solution to decrease the dielectric loss of lead magnesium niobate-lead titanate and it also works well for lead indium niobate-lead magnesium niobate-lead titanate. An outstanding specific detectivity D* of about 1.1 · 10 9 cm-Hz 1/2/W was achieved at a frequency of 2 Hz for Mn-doped lead magnesium niobate-based detectors. © 2012 IEEE. Source

IBULE PHOTONICS Co. | Date: 2012-12-11

Digital cameras; infrared cameras; acceleration sensors; distance measuring apparatus; range finders; metal detectors for industrial or military purposes; resonators; probes for scientific purposes, namely, for testing printed circuit boards; measuring instruments, namely, saccharometers; testing apparatus for testing printed circuit boards; diagnostic apparatus for printed circuit boards; marine depth finders; echo sounding apparatus and machines; water level indicators; automatic liquid-level control machines and instruments; gyrometers; precision measuring apparatus for printed circuit boards; precision measuring machines for printed circuit boards; measuring instruments for printed circuit boards; ultrasonic thickness gauges for animals skins for non-medical use; electronic ultrasonic test equipment, namely, thickness measurers for leather; ultrasonic heat sensors; acoustic sound alarms; alarms for the detection of inflammable gases; dry cells; electric batteries; self-charging batteries; batteries that charge wirelessly; electroacoustic transducers; headphones; audio speakers; panel loud speakers; microphones; frequency converter for actuators; wireless communication device for voice transmission; apparatus for wireless transmission of acoustic information; earphones; microphones for telecommunication apparatus; portable communications apparatus, namely, cellular telephones; roentgen cameras, not for medical purposes; lasers, not for medical purposes; hydrophone machines and apparatus for printed circuit boards; sonars; echo sounders; sound locating instruments, namely, echo sounders; electron microscopes; ultrasonic echo sounders; ultrasonic flaw detectors; ultrasonic sensors; ultrasonic sensor probes, not for medical purposes; protective helmets; protective helmets for sports; motorcycle helmets. Rigid and flexible endoscopes for medical use; high frequency electromagnetic therapy apparatus; apparatus for the treatment of deafness, namely, hearing aids; esthetic massage apparatus; radiotherapy apparatus; heartbeat measuring apparatus; electrocardiographs; roentgen apparatus for medical purposes, namely, monitoring vital signs of patients; massage apparatus for medical purposes; radiological apparatus for medical purposes; medical hearing instruments and parts of such devices; ultrasonic diagnostic apparatus for medical purposes; probes for medical purposes; mobile monitoring scanners for monitoring vital signs of patients; apparatus for clinical diagnosis; ultraviolet radiator units for therapeutic purposes; low frequency electric therapy apparatus; infrared radiator units for therapeutic purposes; electric hearing aids; galvanic therapeutic appliances for the treatment of heart and brain disease; stethoscopes; ultrasonic short wave therapy machines and apparatus; ultrasonic therapy machines and apparatus; X-ray appliances for dental and medical use; devices for measuring blood sugar; arterial blood pressure measuring apparatus; blood testing apparatus; apparatus for blood analysis; ultrasonic probes for medical purposes; ultrasonic medical diagnostic apparatus.

Ibule Photonics Co. | Date: 2013-10-20

Clocks; Parts for watches; Wrist watches.

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