Method for producing electric trigger elements for pyrotechnic articles

Abstract

The invention relates to a method for producing electric trigger elements for pyrotechnic articles such as fuses or igniters, wherein, in a first stage, a) a lacquer is applied by photolithography to an electrically non-conductive substrate, b) a conductive material having a specific resistance of 0.1 *mm to 5.0 *mm is applied to the lacquer and substrate by means of a PVD process in a layer thickness of 0.02 m to 8.0 m, and c) the lacquer is removed from the substrate, and possibly, in a second stage, d) a photolithographic process is again carried out in which a precisely defined region of the resistor strip is covered with photoresist, e) the entire substrate surface is covered with a layer of a metal having a specific resistance of 0.01 *mm to 0.1 *mm in a thickness of 0.1 m to 20 m, wherein the application of the metal is configured such that in regions which have a bare substrate from the first photolithographic process, no metal adheres, and f) the lacquer from the second photolithographic process is again removed.

Claims

1. A method for producing electric trigger elements for pyrotechnic articles, comprising, in a first stage, a) a coating is applied to defined regions of an electrically non-conductive substrate by photolithography, b) a conductive material is applied to the coating and substrate by means of a PVD process in a layer thickness of 0.02 m to 8.0 m, and c) the coating is removed from the substrate to provide a resistor strip; and, in a second stage, d) a photolithographic process is again carried out in which a precisely defined region of the resistor strip is covered with a second coating, e) the entire substrate surface is covered with a layer of a metal in a thickness of 0.1 m to 20 m, wherein the application of the metal is configured such that in regions which have a bare substrate from the first photolithographic process, no metal adheres, and f) the second coating from the second photolithographic process is again removed.

2. The method as claimed in claim 1, wherein the first and second stage provide a resistor layer having a width defined by the photolithographic process in the first stage, and insulation is provided in the surrounding regions.

3. The method as claimed in claim 2, wherein a length of the resistor layer is defined by the photolithographic process in the second stage.

4. The method as claimed in claim 3, wherein a thickness of the resistor layer is determined by the PVD process in step b).

5. The method as claimed in claim 1, wherein the conductive material applied in step b) is configured in a thickness exceeding the desired resistance value and by step-wise removal, the thickness is reduced and thereby the resistance is precisely set.

6. The method as claimed in claim 1, wherein, in step e), a readily conductive layer is applied.

7. The method as claimed in claim 1, wherein the first and second stages provide a resistor layer having a length defined by the photolithographic process in the second stage.

8. The method as claimed in claim 7, wherein a thickness of the resistor layer is determined by the PVD process in step b).

9. The method as claimed in claim 1, wherein the first and second stages provide a resistor layer having a thickness determined by the PVD process in step b).

10. The method as claimed in claim 1, wherein the coating applied in step a) is a photoresist.

11. The method as claimed in claim 10, wherein the second coating applied in step d) is a photoresist.

12. The method as claimed in claim 1, wherein the second coating applied in step d) is a photoresist.

13. The method as claimed in claim 1, wherein the conductive material has a specific resistance of 0.1 *m to 5.0 *m.

14. The method as claimed in claim 13, wherein the metal has a specific resistance of 0.01 *m to 0.1 *m.

15. The method as claimed in claim 1, wherein the metal has a specific resistance of 0.01 *m to 0.1 *m.

16. The method as claimed in claim 1, wherein the entire substrate surface is covered with a layer of a metal in a thickness of 0.1 m to 20 m by galvanic gilding.

17. A method for producing electric trigger elements for pyrotechnic articles, comprising: applying a lacquer in a first photolithography step onto an electrically non-conductive substrate such as to substantially coat a large region of the substrate but leaving free a region of the substrate surface of precisely defined width; using a PVD process to apply an electrically conductive layer onto the lacquer-coated and uncoated regions of the substrate; removing the lacquer coating and thereto adhering electrically conducting layer from the substrate thereby obtaining an electrically conductive resistor layer on the substrate of precisely defined width and having a suitably high specific resistance through which electric current can flow from a first to a second terminal pole of the trigger element at the substrate; applying a photoresist in a second photolithography step onto a precisely defined region of the resistor layer to define a length of the resistor layer; covering the entire substrate surface with a relatively thick layer of readily conductive metal, whereby the application of the metal is configured so that no metal adheres in regions which have a bare substrate from the first lithographic step; and removing the photoresist from the second photolithographic process, whereby a precisely defined resistor region remains which is formed by the conductive layer with high specific resistance, the first photolithographic step setting the width of the resistor layer and providing for insulation in the surrounding regions, the second photolithographic step setting the length of the resistor layer and enabling through the layer of conductive metal good electrical conductivity and good contact at the terminal poles.

18. The method as claimed in claim 17, wherein a final thickness of the resistor layer is set using the PVD process.

19. The method as claimed in claim 17, wherein the PVD-applied electrically conductive layer is applied in excess thickness and the thickness is subsequently reduced by step-wise removal of excess electrically conductive layer for precise setting of the electric resistance of the resistor layer.

20. The method as claimed in claim 17, wherein the readily conductive metal is applied using galvanic gilding.

21. The method as claimed in claim 17, wherein the conductive material has a specific resistance of 0.1 *m to 5.0 *m.

22. The method as claimed in claim 21, wherein the metal has a specific resistance of 0.01 *m to 0.1 *m.

23. The method as claimed in claim 17, wherein the metal has a specific resistance of 0.01 *m to 0.1 *m.

24. The method as claimed in claim 17, wherein the conductive material resistor layer has a thickness of 0.02 m to 8.0 m and/or the conductive metal layer has a thickness of 0.1 m to 20 m.

Description

(1) The invention relates to: a method for producing electric trigger elements for pyrotechnic articles, wherein in a first stage a) a lacquer is applied by photolithography to an electrically non-conductive substrate, b) a conductive material having a specific resistance of 0.1 *m to 5.0 *m is applied to the lacquer and substrate by means of a PVD process in a layer thickness of 0.02 m to 8.0 m, and c) the lacquer is removed from the substrate and possibly, in a second stage, d) a photolithographic process is again carried out in which a precisely defined region of the resistor strip is covered with photoresist, e) the entire substrate surface is covered with a layer of a metal having a specific resistance of 0.01 *m to 0.1 *m in a thickness of 0.1 m to 20 m, wherein the application of the metal is configured such that in regions which have a bare substrate from the first photolithographic process, no metal adheres, and f) the lacquer from the second photolithographic process is again removed; a method in which, in the first stage, the width of the resistor layer is defined by the photolithographic process and insulation is provided in the surrounding regions; a method in which, in the second stage, the length of the resistor layer is defined by the photolithographic process; a method in which a conductive material having a specific resistance of 0.1 *m to 5.0 *m is applied by means of the PVD process in a layer thickness of 0.02 m to 8.0 m, and in step b) the thickness of the resistor layer is defined; a method in which the layer applied in step b) is applied at a thickness exceeding the desired resistance value and by step-wise removal, the thickness is reduced and thereby the resistance is precisely set; a method in which, in the event that no reinforcement of the contact surfaces by means of additional readily conductive layers is required, the entire resistor geometry is realized with a photomask in a single lithographic process; a method wherein possibly in step e) an electrically readily conductive layer is applied; the use of the method for producing pyrotechnic trigger elements, and thus the photolithographic creation of resistor layers with precisely defined geometry on a non-conductive substrate, the stipulation of the length and width of the resistor layer by using photomasks for specific curing of photoresist, and the use of the production method described for pyrotechnic trigger elements.

(2) The special advantages of this method lie therein that very precisely defined edges of the resistor film come about and the material is homogeneous over the entire resistor area (no material changes due to point-wise heat effects as with laser machining). Furthermore, using photomasks, the resistor can be applied simultaneously for very many trigger elements and the parts must be separated at a later time point in the production process, which makes the process quicker and more economic than conventional methods.