Appeal No. 1997-0947
Application 08/385,926
BACKGROUND
The subject matter on appeal is directed to the field of piezoelectric-electrostrictive (P/E) film
elements which are used for purposes such as microphones, sensors, inkjet printers, etc. (specification,
page 1). As indicated in the specification, appellants recognized that prior art P/E devices suffered
from the problem that the P/E layer of the P/E unit suffers stress due to firing shrinkage, thereby causing
the P/E film element not to exhibit its inherent piezoelectric/electrostrictive characteristics (specification,
page 5). Appellants also recognized that when multiple P/E units are placed together on a substrate,
the firing of one P/E unit may interfere with other P/E units on the same substrate, resulting in a reduced
displacement of the diaphragm portions of the affected P/E units (specification, pages 5 to 6). To
overcome this problem, appellants provide a substrate having a window and a convex diaphragm
portion formed integrally therein, with a P/E film element consisting of upper and lower electrodes and a
P/E layer sandwiched in between, wherein the P/E unit is laminated on the convex diaphragm by a film-
forming method (see independent claim 1 on appeal and Figure 3). As stated by appellants in their
specification, this arrangement converts stress and strain in the P/E unit with high efficiency and prevents
a reduction in displacement amount when more than two P/E units formed on a substrate are actuated
simultaneously (specification, page 5). The P/E film element recited by appellants in their claims on
appeal effectively achieves the goals of reduced cross-talk between adjacent P/E units, increases
diaphragm displacement and operating response, and increases mechanical strength of the diaphragm
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