Appeal No. 96-0019
Application 08/150,742
mere selection of optimum values and is unobvious [brief, pages
3-4].
The examiner responds that the differences in materials
used by appellant and Fukino account for the differences in
intervals used, and the artisan would have found appellant’s
intervals obvious in equalizing temperatures for appellant’s
prior art transistor [answer, page 3].
We agree with the position taken by the examiner. The
artisan would have appreciated that the temperature distribution
in a plural emitter junction transistor is affected by all the
materials used and by all the dimensions of the various layers.
That is, different semiconductor materials, insulating materials
and metallic materials have different thermal conductivities and
would, therefore, have an effect on the temperature distribution
of the transistor. Likewise, the dimensions chosen for the
various layers would affect the temperature distribution.
Finally, the range of currents for which the transistor was
designed would dictate the amounts of heat which would have to be
accounted for. All these factors would be taken into account in
determining the optimum spacing as taught by Fukino.
Alderstein teaches that transistors constructed of the
materials disclosed by appellant were known devices in the prior
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