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Conductive Polymer Composites: Conductive Pen for Use in Electronic Notebook Computers

IP.com Disclosure Number: IPCOM000121840D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Afzali-Ardakani, A: AUTHOR [+5]

Abstract

Disclosed is a material and method of manufacture of polymer-carbon composites which could be molded and machined to a pen tip for use in electronic notebooks.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 98% of the total text.

Conductive Polymer Composites: Conductive Pen for Use in Electronic
Notebook Computers

      Disclosed is a material and method of manufacture of
polymer-carbon composites which could be molded and machined to a pen
tip for use in electronic notebooks.

      Styli for resistive film digitizers used in handwriting capture
applications, such as notebook computers, must satisfy requirements
from both the system design (bulk and contact resistance) and the
user (drag of the pen on thin film resistor).

      Among various thermoplastics and conductive pigments which
could be used to fabricate the conductive stylus, polycarbonate and
carbon powder give the most satisfactory combination of electrical
and mechanical properties.  Thus, polycarbonate (LEXAN) (Trademark of
General Electric Co.) is mixed with conductive carbon powder and the
mixture is milled at high temperature in a melt extruder.  The
composite is extruded as a rod which is machined to a pen tip.  The
optimum carbon loading of 27-30% results in a stylus with 0.6-1.0
ohm/cm resistivity which is well in the range of the electrical
requirements for the pen.  The uniformity and the conductivity of the
composite can be enhanced by the addition of small amounts (0.1-0.5%)
of an organotitanate coupling agent KRTTS (Trademark of Kenrich
Chemical Co.).  Addition of the latter also helps to reduce the melt
viscosity of the mixture which results in higher throughput for the
composite pens.

      Disclose...