Ignition element

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• and
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to dielectric heating through the application of a high frequency alternating electric field to said first and second material layers.

An apparatus for initiating the flow of inflation fluid from an inflator for inflating an inflatable vehicle occupant protection device, said apparatus comprising:

• a housing defining a chamber and including a pair of electrical conductors electrically insulated from one another and said housing;
• first ignitable material in the chamber for producing, upon ignition, combustion products which effect the flow of inflation fluid from the inflator;
• second ignitable material in the chamber adjacent said first ignitable material, said second ignitable material being temperature sensitive, said second ignitable material igniting upon the temperature of at least a portion of said second ignitable material increasing to a predetermined temperature and thereby igniting said first ignitable material;
• and
• means for increasing the temperature of said second ignitable material to the predetermined temperature in response to electrical energization, said temperature increasing means contacting said second ignitable material, said temperature increasing means comprising:
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer;
• first conducting means for conducting electrical energy between one of said conductors and said first material layer;
• second conducting means for conducting electrical energy between the other of said conductors and said second material layer;
• and
• a dielectric material disposed in the space between said overlying portions of said first and second material layers, said dielectric material heating said portion of said second ignitable material to the predetermined temperature upon the application of a high frequency alternating electric field to said dielectric material.

An apparatus comprising:

• a body of pyrotechnic material;
• an initiator disposed adjacent to said body of pyrotechnic material, said initiator including a body of dielectric material, with said body of dielectric material being ineffective to conduct direct current to prevent ignition of said body of pyrotechnic material upon application of direct current to said body of dielectric material;
• and
• circuit means for applying a high frequency alternating electric field to said body of dielectric material to heat said body of dielectric material to a temperature sufficient to effect ignition of said body of pyrotechnic material under the influence of heat transferred from said body of dielectric material to said body of pyrotechnic material.

An apparatus comprising:

• a body of pyrotechnic material;
• an initiator disposed adjacent to said body of pyrotechnic material, said initiator including a body of dielectric material, said body of dielectric material having a dielectric constant which is between about 300,000 and about 500,000 and a dielectric loss tangent of less than about 0.3;
• and
• circuit means for applying a high frequency alternating electric field to said body of dielectric material to heat said body of dielectric material to a temperature sufficient to effect ignition of said body of pyrotechnic material under the influence of heat transferred from said body of dielectric material to said body of pyrotechnic material.

An apparatus comprising:

• a body of pyrotechnic material;
• an initiator disposed adjacent to said body of pyrotechnic material, said initiator including a body of dielectric material, said body of dielectric material including a ferroelectric ceramic;
• and
• circuit means for applying a high frequency alternating electric field to said body of dielectric material to heat said body of dielectric material to a temperature sufficient to effect ignition of said body of pyrotechnic material under the influence of heat transferred from said body of dielectric material to said body of pyrotechnic material.

An apparatus comprising:

• a body of pyrotechnic material;
• an initiator disposed adjacent to said body of pyrotechnic material, said initiator including a body of dielectric material comprising a perovskite structured ferroelectric material;
• and
• circuit means for applying a high frequency alternating electric field to said body of dielectric material to heat said body of dielectric material to a temperature sufficient to effect ignition of said body of pyrotechnic material under the influence of heat transferred from said body of dielectric material to said body of pyrotechnic material.

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• and
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to the application of a high frequency alternating electric field to said first and second material layers, wherein said dielectric material comprises a perovskite structured ferroelectric material.

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to the application of a high frequency alternating electric field to said first and second material layers;
• and
• an electrically insulating member which supports said first and second material layers.

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• and
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to the application of a high frequency alternating electric field to said first and second material layers, said high frequency alternating electric field having a frequency in the range of about 900 kHz to about 1 MHz.

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, said overlying portions of said first and second material layers are spaced apart a distance no greater than about 0.000006 m (6 .mu.m), with at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• and
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to the application of a high frequency alternating electric field to said first and second material layers.

An apparatus for heating temperature sensitive ignitable material, said apparatus comprising:

• a body of pyrotechnic material;
• an electrically conductive first material layer;
• an electrically conductive second material layer having a portion spaced from and overlying a portion of said first material layer, at least one of said first and second material layers being disposed adjacent to said body of pyrotechnic material;
• and
• a dielectric material disposed between said overlying portions of said first and second material layers, the temperature of said dielectric material increasing to ignite said body of pyrotechnic material in response to the application of a high frequency alternating electric field to said first and second material layers, with said dielectric material having a dielectric constant in the range of about 300,000 to about 500,000.