The Hong Kong Polytechnic University

Asm Assembly Automation Limited

Other

Asm Technology Singapore Pte Ltd

Siu Wing Or

Chou Kee Peter Liu

Ping Kong Joseph Choy

Lai Wa Helen Chan-Wong

Helen Lai Wa Chan-Wong

Chung Sheung Yung

Helen Lai Wa Chan

Chung Loong Choy

Yam Mo Wong

Yiu Ming Cheung

Yiqing Ni

Honghai Zhu

Lai Wa Chan-Wong

Kei Chun Cheng

Honyu Ng

Yuanfeng Duan

Chung Shueng Yung

Siu San Chiu

An magnetorheological damper useful in structural vibration control has a damper body and a moveable portion relative to the damper body. The damper includes an magnetorheological material contained within the damper body for resisting movement of the moveable portion. Rheology changes can be generated in the magnetorheological material owing to changes in a magnetic field, to which the magnetorheological material is exposed. The damper further includes at least a sensor embedded in the damper for monitoring an external force exerted on the damper, and for generating a signal to control the magnetic field and hence the resulting yield force and rheological damping of the damper in response to a variance in the external force.

Magnetorheological damper and use thereof

A damping apparatus is provided for a positioning stage that is operative to move and position an object along a motion axis. The damping apparatus comprises a motion transformation device operative to rotate the positioning stage about a rotary axis that is substantially perpendicular to the motion axis, in response to forces generated to the positioning stage during acceleration or deceleration thereof. Resilient elements connected to the positioning stage serve to reduce transmission of vibration generated from the positioning stage.

Active damping device for a positioning stage

An ultrasonic transducer driver has a giant magnetostrictive element, a fastener for holding the giant magnetostrictive element under mechanical pressure, a first field generator for providing a magnetic bias field, a second field generator for providing a magnetic drive field and a magnetic circuit for channelling the magnetic fields in the magnetostrictive element. An ultrasonic transducer for a bonding apparatus has a horn having a bonding tool at its smaller end and a mounting barrel adjoined onto it. The driver coupled to the larger end of the horn.

Driver for an ultrasonic transducer and an ultrasonic transducer

A tunable vibration absorption device is provided that is suitable for active or semi-active vibration absorption or damping of vibrations in vibrating structures. It comprises a stack including a force actuator mechanism for generating an axial actuation force and a force sensor mechanism which is responsive to an external force acting on the stack to generate a force signal. A controller unit is electrically connected to the force sensor mechanism for receiving the force signal generated by the force sensor mechanism, and it is also electrically connected to the force actuator mechanism for adjusting the axial actuation force generated by the force actuator mechanism in response to the received force signal generated by the force sensor mechanism.

Tunable vibration absorption device

The operational frequency of existing magnetoelectric materials having metallic or ceramic magnetostrictive materials and ceramic piezoelectric materials may be limited to a few kilohertz due to the presence of eddy-current losses in the metallic magnetostrictive phase. Further, these materials may be difficult to machine and fabricate due to their brittleness. Additionally, it may be difficult to tailor and optimize the properties (i.e., magnetoelectric voltage coefficient &#x3b1;, etc.) of the devices. This invention provides a magnetoelectric element including at least one set of alternating piezoelectric layers and magnetostrictive composite layers. The magnetostrictive composite layer includes at least one magnetostrictive material dispersed in first concentrated zones within a first polymer matrix, wherein all of the concentrated zones are orientated along a first direction. It is found that the conversion efficiency (i.e., &#x3b1;) varies in accordance with applied magnetic control field H.

Magnetoelectric devices and methods of using same

A piezoelectric device is provided that comprises a mechanical amplifier adapted to produce a displacement output and/or receive a force input, and first and second flexible platforms connected to the mechanical amplifier. The first flexible platform is connected to one side of the mechanical amplifier and piezoelectric material is mounted on the first flexible platform for controllably flexing the first flexible platform. The second flexible platform is connected to another side of the mechanical amplifier and piezoelectric material is mounted to the second flexible platform for controllably flexing the second flexible platform.

Piezoelectric device with amplifying mechanism

The operational frequency of existing magnetoelectric materials having metallic or ceramic magnetostrictive materials and ceramic piezoelectric materials may be limited to a few kilohertz due to the presence of eddy-current losses in the metallic magnetostrictive phase. Further, these materials may be difficult to machine and fabricate due to their brittleness. Additionally, it may be difficult to tailor and optimize the properties (i.e., magnetoelectric voltage coefficient &#x3b1;, etc.) of the devices. This invention provides a magnetoelectric element including at least one set of alternative piezoelectric layer and magnetostrictive composite layer. The magnetostrictive composite layer includes at least one magnetostrictive material dispersed in first concentrated zones within a first polymer matrix, wherein all of said concentrated zones are orientated along a first direction. It is found that the conversion efficiency (i.e., &#x3b1;) varies in accordance with applied magnetic control field H.

A method of bonding wires between a semiconductor die and a substrate on which the die is mounted includes providing an ultrasonic transducer ( ). The transducer ( ) includes an ultrasonic energy generation device ( ), an ultrasonic vibration amplifying device ( ) coupled at one end ( ) to the ultrasonic energy generation device ( ), a bonding tool ( ) coupled to the opposite end ( ) of the ultrasonic vibration amplifying device ( ), and a mounting structure ( ) located between the ends ( ) of the ultrasonic vibration amplifying device ( ). The method also includes performing a first wire bond by operating the ultrasonic transducer ( ) at a first ultrasonic frequency and performing a second wire bond by operating the ultrasonic transducer ( ) at a second ultrasonic frequency, the second ultrasonic frequency being different from the first ultrasonic frequency.

Method of bonding wires

A bonding tool has a driver of piezoelectric elements in a stack. A sensor is positioned and held in the stack and includes a piezoelectric element sandwiched between electrodes and insulating wafers. Voltage developed between the electrodes is monitored and used to determine a bonding parameter, including the amplitude and duration of each ultrasonic burst.

Ultrasonic transducer

A sensor for an ultrasonic bonding apparatus comprises a piezoelectric material located between the ultrasonic transducer and an ultrasonic concentrator of the bonding apparatus. The sensor has at least two outputs for measuring different bonding parameters, the outputs being chosen to optimize the signal response for the bonding parameters in question.

Piezoelectric sensor for measuring bonding parameters

A bonding tool for applying pressure and ultrasonic energy simultaneously to join miniature components together includes an ultrasonic driver having four composite wafers separated by electrodes. Such bonding tools are known that use wafers made of wholly of ceramic material. By using wafers having four sector parts of ceramic material separated by layers of polymer as shown, bonding tools are provided with broader bandwidth operation and reduced spurious resonance modes.

Growing community of inventors

Hong Kong, China

Siu Wing Or