| (19) |
 |
|
(11) |
EP 0 339 746 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
03.07.1991 Bulletin 1991/27 |
| (43) |
Date of publication A2: |
|
02.11.1989 Bulletin 1989/44 |
| (22) |
Date of filing: 25.04.1989 |
|
|
| (84) |
Designated Contracting States: |
|
DE FR GB NL |
| (30) |
Priority: |
29.04.1988 US 187754
|
| (71) |
Applicant: SHELL INTERNATIONALE RESEARCH
MAATSCHAPPIJ B.V. |
|
NL-2596 HR Den Haag (NL) |
|
| (72) |
Inventor: |
|
- Rambow, Frederick Henry Kreisler
Houston
Texas 77096 (US)
|
|
| |
|
| (54) |
Acoustic transducer backing in the shape of a Wood's horn |
(57) The unwanted acoustic energy from the back side of an acoustic transducer (25) is
fully absorbed in a Wood's Horn styled acoustic energy trap (30) embedded in an acoustically
absorbing material (35). Also, the impedance of the transducer (25) and backing (30)
can be exactly matched, thereby increasing the frequency bandwidth.