United States Patent [w]
Barthe et al.
US006049159A [ii] Patent Number: [45] Date of Patent:
[54] WIDEBAND ACOUSTIC TRANSDUCER
[75] Inventors: Peter G. Barthe, Phoenix; Michael H. Slayton, Tempe, both of Ariz.
[73] Assignee: Albatros Technologies, Inc., Mesa, Ariz.
[21] Appl. No.: 08/944,261 [22] Filed: Oct. 6, 1997
[51] Int. CI.7 A61B 8/00; H01L 41/08
[52] U.S. CI 310/334; 310/326
[58] Field of Search 310/322, 326,
310/334, 327, 335; 181/139, 142
[56] References Cited
U.S. PATENT DOCUMENTS
2,427,348 9/1947 Bond et al 310/327
4,166,967 9/1979 Benes et al 310/322
4.211.948 7/1980 Smith et al 310/322
4.211.949 7/1980 Brisken et al 310/322
4,507,582 3/1985 Glenn 310/327
4,672,591 6/1987 Breimesser et al 367/152
4,680,499 7/1987 Umemura et al 310/334
4,771,205 9/1988 Mequio 310/334
5,030,874 7/1991 Saito et al 310/334
5,070,879 12/1991 Herres 128/660.08
5,163,436 11/1992 Saitoh et al 310/335
5,212,671 5/1993 Fujii et al 367/151
5,305,756 4/1994 Entrekin et al 128/660.09
5,327,895 7/1994 Hashimoto et al 128/662.03
5,392,259 2/1995 Bolorforosh 310/334
5,396,143 3/1995 Seyed-Bolorforosh et al 310/334
5,423,220 6/1995 Finsterwald et al 73/642
5,438,998 8/1995 Hanafy 310/334
5,503,152 4/1996 Oakley et al 128/661.01
5,526,815 6/1996 Granz et al 128/660.03
5,558,092 9/1996 Unger et al 128/660.03
5,644,085 7/1997 Lorraine et al 310/334
5,706,252 1/1998 Le Verrier et al 310/334
5,706,564 1/1998 Rhyne 310/327
5,779,644 7/1998 Eberle et al 600/463
5,792,058 8/1998 Lee 600/459
5,810,009 9/1998 Mine et al 310/334
FOREIGN PATENT DOCUMENTS
190 948 8/1986 European Pat. Off 310/327
0 490 260 A2 6/1992 European Pat. Off B06B 1/06
60-12899 1/1985 Japan 310/327
Primary Examiner—-Thomas M. Dougherty
Attorney, Agent, or Firm—Snell & Wilmer
[57] ABSTRACT
A transducer according to various aspects of the present invention provides high fractional bandwidth with relatively low degradation of the pulse duration and sensitivity. The transducer includes a back matching layer behind the transducer material. The back matching layer is characterized by an impedance selected to transmit a selected portion of the backwards propagating acoustic energy to an absorption layer. The remaining acoustic energy is reflected in the desired direction of propagation. As a result, the transducer provides enhanced bandwidth without excessive loss of sensitivity or increase in pulse duration.
31 Claims, 9 Drawing Sheets
