Method for making comb electrode for electrical recording apparatus

Claim 1

Method to make a comb electrode array for electric recording apparatus, particularly for use with metallizing strip recording media, to provide closely spaced elongated conductive strip electrodes (22), insulated from each other by an insulating gap and having a recording terminal end portion (22), the other end portion being formed as a connecting portion (26) for connection to an external circuit, the steps of providing a thin sheet of springy, hard sheet metal (10); coating the sheet metal on both surfaces with a photosensitive layer (11,12); providing a first mask (13) having transparent areas corresponding to the electrode configuration and, in addition, having transparent areas (15, 16, 17) crossing said electrode configuration, the additional crossing transparent areas being located between said end portions to place the connecting portions (18, 19) between said end portions (22, 26) of the electrodes; providing a second mask (14) at least having transparent areas corresponding to the electrode configuration; applying the first mask (13) to one side of the sheet; applying the other mask (14) to the other side of the sheet; exposing both sides of the sheet through the respective mask, and developing the sides of the sheet by polymerizing those portions of the photo-sensitive layers which were beneath transparent areas of the mask and removing the photo-sensitive layer portions which were under opaque areas of the mask; etching both sides of the developed sheet, the additional transparent areas thereby leaving connecting bridge portions (18, 19, 20; 33, 34) between the electrodes to provide for a mechanically stable sub-assembly suitable for further handling; adhering the attached electrode sub-assembly array on a carrier substrate (23, 28) located against the side adjacent the second mask; and removing the connecting portions (18, 19, 20; 33, 34) after the sub-assembly has been adhered to said carrier substrate (23, 28).