The Hong Kong Polytechnic University

Kin Wing Kwok

Chen Chao

Helen Lai Wa Chan

Xiaoxing Wang

Siu Hong Choy

Helen Lai Wah Chan

Tin Yan Lam

An apparatus and method for detecting the oscillation amplitude of a bonding tool includes a sensing unit disposed adjacent to and at a distance from the bonding tool. The sensing unit includes a pair of electrodes, a piezoelectric sensing layer located between the pair of electrodes, and a membrane associated with the piezoelectric sensing layer. The piezoelectric sensing layer becomes sensitive to ultrasonic vibrations and generates electrical voltage signals after being activated by a poling process. An optional pre-amplifier is used to amplify the signals generated from the sensing unit, and an oscilloscope is used to further process the signals.

Method and apparatus for measuring oscillation amplitude of an ultrasonic device

The present invention provides a piezoelectric ceramic composition, especially a lead-free piezoelectric ceramic composition, with a suitable amount of CeOor CeO-containing complex additives, which is represented by the following formula: (NaKLi)(NbA)O+yCeO+zBOwherein 'A' represents Sb or Sb+Ta, 'B' represents a tetravalent transition metal, 0&#x2266;x&#x2266;0.2, 0.2 wt %&#x3c;y&#x3c;1.2 wt % and 0&#x2266;z 1 wt %. Addition of CeOor CeO-containing complex additives suppresses melting and abnormal grain growth of (NaKLi)(NbA)Oduring sintering, thereby improving sinterability and increasing the density of the composition. As a result, the dielectric and piezoelectric properties of the ceramics are enhanced. Furthermore, the represented compositions have a wide sintering temperature range so that the process for preparing such a lead-free piezoelectric ceramic composition has high degree efficiency.

Piezoelectric ceramic composition and the method for preparing the same

Growing community of inventors

Hong Kong, China

Kin Wing Kwok