Appeal No. 1998-0091
Application No. 08/404,054
capacitance of the device vary as a function of humidity
(col. 1, lines 26-52). Hegner explains that this effect is
due to the fact that the uncovered portions of the substrate
and diaphragm lose oxygen or nitrogen atoms, i.e., become
reduced (col. 1, line 67 to col. 2, line 7). Referring to
Figure 2, Hegner covers the facing surfaces of electrodes 14
and 15 on diaphragm 11 and substrate 12 with protective layers
21 and 22, respectively, made, for example, from one of the
oxides of the material of which the electrode is formed
(col. 4, lines 15-21). Appellants do not challenge the
examiner's taking of official notice (Final Rejection at 6)
that these oxide layers are insulating materials. Referring
to Figure 4, protective layers 21 and 22 and the uncovered
facing surface areas of diaphragm 11 and substrate 12 are then
covered with spin-on glass layers 23, which "surprisingly
seal[] the uncovered surface portions of diaphragm 11 . . .
and substrate 12 . . . so perfectly that the above-mentioned
reduction during the brazing process practically no longer
occurs" (col. 5, lines 52-57). Hegner does not explain what
type of protection is being provided by his protective layers
-9-
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