The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 12, 1985
Filed:
Mar. 18, 1983
Philip H Wisbey, Colchester, GB;
The Marconi Company Limited, Stanmore, GB;
Abstract
In the manufacture of surface acoustic wave devices it is necessary to manufacture master patterns from which interdigitated electrodes are produced photographically. The manufacture of the master is expensive and a new master is needed for each new device required to operate at a different frequency. The invention overcomes this problem in the device shown in FIG. 1 by the use of transducers 2 and 5, each constituted by separate groups 3 or 6 of interdigitated fingers. The effect of this is for the transducer to have peak frequency responses at a whole series of frequency values. These frequency values can be shifted up or down by varying the velocity of the surface acoustic waves in the region of the appropriate transducer. This is done using any one of a number of different methods but, in the embodiment of FIG. 1, metal layers 8 and 9 are applied and then adjusted in size until a peak of the transducer 2 coincides, at the desired frequency, with a peak of the transducer 5. In this way two masters for producing electrodes in the patterns shown as 2 and 5 in FIG. 1 can be used in the manufacture of surface acoustic wave devices having a whole range of different frequency responses.