Etching apparatus for accurately making small holes in thick materials
Patent 4013498 Issued on March 22, 1977. Estimated Expiration Date: 
March 22, 1994. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 22, 1994. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2052962 3197324 3431637 3679500 InventorsApplicationNo. 05/617682 filed on 09/29/1975US Classes:156/345.19, With mechanical mask or shield or shutter for shielding workpiece156/345.2, Running length workpiece (e.g., etching indeterminate length strip)156/345.21, Liquid etchant spray type156/345.22, With plural etching zones for a single discrete workpiece in apparatus216/47, Mask is multilayer resist216/92Projecting etchant against a moving substrate or controlling the angle or pattern projection of the etchant or controlling the angle or pattern of movement of the substrateExaminersPrimary: Powell, William A.Attorney, Agent or FirmAbstractA sheet of metallic material having a thickness T is covered on one side by an etchant resist and on the opposite side by an etchant resist and a removable shield. Etching is first performed on the side with only the etchant resist layer. Next, the shield is removed and the material is etched from both sides to produce an opening having a minimum dimension less than the thickness T of the material. | |
