Thin film bridge initiators and method of manufacture

• US 5,732,634 A
• Filed: 09/03/1996
• Issued: 03/31/1998
• Est. Priority Date: 09/03/1996
• Status: Expired due to Term

• Current Assignee: First Union National Bank As Administrative AGEN
• Original Assignee: Teledyne Industries Incorporated (Teledyne Technologies Incorporated)
• Inventors: Flickinger, Joseph E., Moran, Gary D., Smith, Brian E.
• Primary Examiner(s): Carone, Michael J.
• Assistant Examiner(s): MONTGOMERY, CHRISTOPHER KEITH
• Application Number:
  US08/706,894
• Time in Patent Office: 574 Days
• Field of Search: 102/202.5, 102/202.7, 102/202.8, 102/202.9, 102/202.12, 102/202.14
• US Class Current: 102/202.5
• CPC Class Codes: F42B 3/125 characterised by the configuration of the bridge initiator case F42B3/11 takes precedence

Abstract

A thin film bridge initiator for initiation of explosives includes a thin film resistive element of a selected composition of Nichrome, alternately Tantalum Nitride either of which is evaporated upon (in the case of Nichrome) or sputtered upon (in the case of Tantalum Nitride) an alumina substrate. A prime explosive mix is contained against the initiator film elements by a positive retention contactor assembly.

Claims

1. A selective, pyrotechnic pretensioner cartridge/air bag initiator comprising:

a) a loaded header assembly (8), securing opposed electrical conductors (10), said conductors being bonded to the header assembly by epoxy eutectic means (9) whereby to contact a superposed thin film bridge, said bridge including a resistive layer (1) having a sheet resistivity of 0.1 to 20 ohms;

b) a prime explosive mix (12) contained by a positive retention compactor assembly (11), said assembly consisting of a contained powder retention device (13) which is disposed between an auxiliary powder plate (14) and a compressive plate (15);

c) an output shell (11'"'"') connected to the header assembly (8), the output shell containing an output load of explosive (12'"'"') which is retained in detonateable relation to the explosive mix (12);

d) a source of electric power connected to the resistive layer (1).

2. A selective, pyrotechnic pretensioner cartridge/airbag initiator according to claim 1 including dielectric ground means (9'"'"') connecting one said electrical conductor (10) to the thin film bridge.

3. The selective pyrotechnic pretensioner cartridge/airbag initiator of claim 2 wherein the ground means is comprised of glass.

4. The selective pyrotechnic pretensioner cartridge/airbag initiator according to claim 1 comprising:

a) a ceramic, alumina substrate (2), having a thickness which is 0.025 inches;

b) a one-to-two micron thick resistive layer (1) of a preselected metal based composition, spanning other bonded metal films;

c) first gold film seed layer, thermally evaporated upon the resistive layer (1) to a thickness of 0.6 to 200 micro-inches;

d) a film of gold plate (4), electroplated upon the first gold film.

5. The thin film initiator of claim 4 wherein the resistive layer (1) is Nichrome.

6. The thin film initiator of claim 4 wherein the resistive layer (1) is Tantalum Nitride.

7. The pyrotechnic pretensioner cartridge of claim 4 wherein the prime explosive mix (12) includes a hydroborate based composition, capable of ignition.

8. A selective pyrotechnic pretensioner cartridge/airbag initiator according to claim 4 including dielectric ground means (9'"'"') connecting one said electrical conductor (10) to the thin film bridge.

9. The selective pyrotechnic pretensioner cartridge/air bag initiator of claim 8 wherein the ground means is comprised of glass.

10. The pyrotechnic pretensioner cartridge of claim 1 wherein the prime explosive mix (12) includes a hydroborate based composition, capable of ignition.