Patents Assigned to S-Cera Co., Ltd.
  • Patent number: 6683014
    Abstract: The present invention provides a piezoelectric ceramic composition having the formula: {[Pb(1−1.5x)±(0˜0.2)Lax][Ti(1−y−z)MnyCuz]O3} which meets the requirements: 0.02<x<0.14, 0.01≦y<0.04, and 0.002≦z≦0.008. The piezoelectric ceramic composition of the present invention can be stably sintered under normal atmosphere. That is, there is no need for an oxygen partial pressure to be 80% or more. Furthermore, the composition exhibits excellent piezoelectric property and thermal stability. Accordingly, the piezoelectric ceramic composition of the present invention has excellent piezoelectric property at a thickness longitudinal third harmonic frequency capable of producing a high frequency of 15 MHz or more, and can be used as a material of a piezoelectric ceramic device with a small electrode area.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: January 27, 2004
    Assignee: S-Cera Co., Ltd.
    Inventors: Dong Hwan Seo, Kang Heon Hur, Jong Kuk Hong, Sang Koo Kwon
  • Patent number: 6656378
    Abstract: Disclosed is a piezoelectric ceramic composition comprising a PZT piezoelectric composition, a B-site of which is substituted with a certain material, and chromium oxide, and a piezoelectric device using the piezoelectric ceramic composition. The piezoelectric ceramic composition has good heat resistance and frequency stability, and reduces a leakage current. There is provided the piezoelectric ceramic composition comprising a main component expressed by Pb[(Co1/2W1/2)xTi1−x−yZry]O3 (wherein, 0.001≦x≦0.04, and 0.35 ≦y≦0.55), Cr2O3 in an amount of 0.01 to 2 wt %, MnO2 in an amount of 0.1 to 0.5 wt %, and an additive in an amount of 0.01 to 2.0 wt %, based on the total weight of the piezoelectric ceramic composition, in which the additive is selected from the group consisting of CoO, MgO, ZnO, Al2O3, Fe2O3, Sb2O3, SnO2, CeO2, Nb2O5, V2O5 and WO3, and mixtures thereof.
    Type: Grant
    Filed: February 8, 2002
    Date of Patent: December 2, 2003
    Assignee: S-Cera Co., Ltd.
    Inventors: Sang Koo Kwon, Kang Heon Hur, Jong Kuk Hong, Dong Hwan Seo