Appeal No. 2000-1075
Application 08/838,910
that doing so is within the skill of the art.
Accordingly, we conclude that the examiner has not carried
the burden of establishing a prima facie case of obviousness of
the oxygen concentration detectors recited in the appellants’
claims 21 and 36. Hence, we reverse the rejection of these
claims and claims 22-26 which depend from claim 21.
Rejection of claim 32
Ker discloses an oxygen concentration detector including a
sensor element comprising a solid electrolyte (14) having
external and internal electrodes (26,22) on external and internal
surfaces (28,24) thereof, respectively, and a heater element (62)
disposed adjacent to the internal electrode to form a clearance
therebetween (figure 1).4 Ker discloses that the base material
of the heater element is a ceramic such as alumina (col. 5,
lines 41-43). The appellants’ specification (page 12, table 1)
indicates that alumina has an emissivity of 0.3. Ker does not
disclose a heater element having an emissivity of 0.6 or more.
Agarwal discloses an oxygen sensor having a heating
element (11,12) arranged to surround and radiate heat to a solid
4 The appellants do not challenge the examiner’s argument
(answer, page 6) that a clearance of at least 0.1 mm would have
been fairly suggested to one of ordinary skill in the art by the
applied prior art.
6
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