Appeal No. 96-4196
Application No. 08/239,010
particular operative environment is a matter of choice to
those skilled in the art, and many other ferrites may be
chosen by a study of their characteristic loss and dissipation
characteristics” (column 4, lines 21 through 27).
We agree with appellants (Brief, pages 7 and 8) that
Philips discloses the use of a sintered polycrystalline
ferrite material for a magnetic recording head or for other
electromagnetic use (page 1, column 2, line 52 through page 2,
column 1, line 12). On the other hand, Johnson discloses a
sintered polycrystalline ferrite material that is used in a
core of a transformer (column 1, lines 7 and 8). Johnson,
like Anderson, is concerned about heating losses within the
ferrite core (column 1, lines 29 through 37; column 4, lines
30 through 54). Examples 1 through 5 in Johnson’s Table 1
show a sintered polycrystalline ferrite core with a grain size
between 0.5 and 2.0 microns that is operated at a frequency of
3 MHZ, and a magnetic flux density of 10 mT to yield losses in
the range 60 mW/cm to 140 mW/cm (column 4, lines 45 through3 3
54).
Inasmuch as Johnson is concerned with reduction of
heating losses in a polycrystalline ferrite core, albeit in a
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