Appeal No. 2006-0412 Παγε 10
Application No. 09/999,827
pressure. Tribo-electric effects deliver large, essentially
static charges, to the pickup electrode.
As set forth on pages 8 and 9:
According to the invention in one aspect, an
electric field sensor is provided that includes a
first pickup electrode for placement next to a surface
whose electrical field is to be sensed through
capacitive coupling. This may be achieved by
avoiding intimate contact with the body e.g. by
positioning the plate of the pickup electrode at a
“stand-off” location that reduces the sensitivity
of the measured output to motion efforts i.e.
variations in the separation of the pick-up electrode
from the surface of the body being sensed. And it may
be achieved by placing a limiting capacitor in series
with the input to the sensing amplifier. To ensure
that “standoff” effort of the invention first
arrangement is achieved, an insulating layer may be
provided over the electrode to separate it from a
body by a gap that ensures that capacitive coupling
does not vary sensitivity with separation. . ..
Brun Del Re adds (page 10) that:
This is completely counter-intuitive to the methodologies
applied by the prior art experiments with capacitive,
“dry” electrodes which employ extremely thin dielectric
layers and then proceed to place the sensor in
intimate contact with the surface of the body being
sensed. Thus, the present invention, in one aspect,
employs a dielectric layer for the pick-up electrode
that ensures that sensing is occurring at a stand-off
location which is insensitive to minor motion and/or
surface irregularities as well as temporal changes in
surface characteeristics [sic, characteristics].
From the disclosure of Brun Del Re, we find that having dry
electrodes press directly against the patient’s body has various
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