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Patents Photochromatic compound use in polymerics Applicant: Great Lakes Chemical (Europe) GmbH, Switzerland This invention relates to photochromatic compounds, and more specifically to photochromatic compounds belonging to the group of spiro-isoindolino-oxazines, a process for their preparation and their use in polymeric materials. A further aim of the present invention relates to polymeric compositions containing photochromatic compounds and the photochromatic articles obtained from their processing. These compounds belonging to the group of spiro-isoindolino-oxazines have excellent photochromic characteristics, excellent stress resistance and high dyability characteristics. Patent number. US 6414057 Publication date. July 2, 2002 Inventors: Luciana Crisci, William Giroldini, Vincenzo Malatesta, Maria Lucia Wis
Force sensing apparatus Applicant: ASM Technology Ltd, Singapore The invention relates to force sensing apparatus and in particular, force sensing apparatus for monitoring the bond force in an ultrasonic welding machine. Ultrasonic welding is commonly used for wire bonding when packaging semiconductor devices and for other bonding operations. Force sensors are used in the ultrasonic wire bonding machines to either monitor the quality of the wire bond by measuring the bond force or to generate the required bond force in response to signals from the sensor. In some arrangements the force sensor is located in a structure which is external from and isolated from the transducer. In other designs, the force sensor is mounted on the transducer body itself. Sensors residing on the body of the ultrasonic transducer are normally of the balanced strain gauge design. They measure the surface strains produced by bending of the transducer during bonding and thus indirectly obtain information regarding the bond force. However, as they contact the transducer body they exert a load on the transducer, which interferes with the operation of the transducer. Force sensors, located in force arms external to the bond-head are, in general, not compact. In general, piezoelectric force sensors and electrorestrictive force sensors suffer from the problem of output voltage drift. This introduces errors in successive measurements.
( Srnart • Materials ) Bulletin
To overcome this problem, a number of the are driven with a single frequency input and machines use two or more sensors to mutually combine two excited resonant mode shapes, compensate for any drift. However, this has the generating an elliptical path to drive a rotor. disadvantage of increasing the cost and size of ::- These motors have the potential of being low the sensor arrangement and also increases the cost and highly efficient, but are limited to uniprocessing required for the sensor signals. In this directional motion. invention force sensing apparatus is provided for In contrast, propagating-wave motors require sensing deflection of a transducer in an two vibration sources to generate two standing ultrasonic welding machine. The apparatus waves. The two standing waves are includes a body member, a transducer holder superimposed to form a propagating wave which and a force sensor. The transducer holder is generates elliptical motion and drives the rotor. adapted to hold an ultrasonic transducer and the Propagating-wave rotary motors have a lower transducer holder is fixed to the body member. potential efficiency, but do offer reversibility. In The force sensor is located between adjacent the past, ultrasonic rotary motors have been surfaces of the body member and the transducer used primarily in small, low torque positioning holder to sense a force applied between the applications. Recently, some designs have surfaces. offered high torque and power performance, but Patent number: US 6425514 still have high energy losses due to friction. Publication date: 30 July, 2002 Consulting a catalogue of commercial motors Inventors: Gang Ou, Gary Peter Widdowson, under 100 horsepower (75 kW) leads to a rough Ka Shing, Kenny Kwan power density of 100 W/kg for typical electric motors. Electric motors and piezoelectric material-based motors have an advantage over Smart material motor with hydraulic systems in that power may be mechanical diodes transferred over long distances with relatively Applicant: Penn State Research Foundation, light wires. USA (Penn State University) As a rule, piezoelectric material-based motors The first smart material motors were of the have advantages over typical electric motors in inchworm-type. A common design feature of that they offer better potential to conform with these devices is a quasi-static clamping and geometric requirements associated with tightlyadvancing of a moving element to generate integrated adaptive structures, and in the motion resembling the way an inchworm walks. potential for reduced electromagnetic field Since the motion of inchworm-type motors is generation. quasi-static, it is most often used in small, Numerous problems exist regarding motors stable, high precision applications with and actuators. These problems include the need relatively high force and low speed for high specific power, reliability, life, and requirements. A second category of smart efficiency. Although these problems exist in material motor is the ultrasonic linear motor. numerous applications, one specific area where These are driven with a low voltage drive signal, these problems surface is in military and are typified by high speed, low force applications. For example, although the military operation. A number of developments have also may be able to track moving targets, it lacks the been made in the field of smart material rotary ability to pursue them. Agile high-speed motors. While ultrasonic rotary motors have weapons, for both air and marine systems, received most of the attention, a number of would address such a need and represent a new recent designs have applied the technology of military capability. Compact, conformable highthe quasi-static inchworm concept to rotary power actuators are needed to enable such motors. These motors are exceptional in terms systems. of torque output, although usually quite slow. This invention is an actuator having a shaft Ultrasonic rotary motors, driven at resonance at delivering mechanical power to a load, a first frequencies in the 20-100 kHz range, are more active element adapted to be driven by an common in the literature than the three types oscillating signal, and at least one mechanical presented. diode operatively connected to the shaft in the As small, lightweight, quiet alternatives to act of development. Several mechanical diodes electromagnetic motors, ultrasonic motors are may also be used. Diodes can be either rotary used in industrial applications such as camera mechanical diodes or linear and bi-directional. lenses, printers, and floppy disk drives. Patent number." US 6429573 Ultrasonic rotary motors, like ultrasonic linear Publication date: August 6, 2002 motors, are divided into two classes by their Inventors." Gary H. Koopmann, Chen mode of operation: standing-wave type, and Weicheng, George A. Lesieutre, Jeremy Frank, propagating-wave type. Standing-wave motors Eric Mockensurm
October 2002