Browse Prior Art Database

Magnetic Pen Inductor

IP.com Disclosure Number: IPCOM000113267D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Riggio Jr, SR: AUTHOR

Abstract

Described is a high-inductance radiating magnetic inductor including a core formed as a hollow cylinder of magnetic material, a first group of coils formed by pulling a wire through the longitudinal hole of the core and lengthwise around the outside of the core, and a second group of coils wound in a helical pattern around the core. These two groups of coils are connected in series, and may in fact be formed using a single wire. An inductor of this type is suitable for use in a magnetic "pen" pointing instrument. This type of instrument is used to provide location information to a tablet computer as the pen is moved along a magnetically sensitive grid on a surface of the computer.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 68% of the total text.

Magnetic Pen Inductor

      Described is a high-inductance radiating magnetic inductor
including a core formed as a hollow cylinder of magnetic material, a
first group of coils formed by pulling a wire through the
longitudinal hole of the core and lengthwise around the outside of
the core, and a second group of coils wound in a helical pattern
around the core.  These two groups of coils are connected in series,
and may in fact be formed using a single wire.  An inductor of this
type is suitable for use in a magnetic "pen" pointing instrument.
This type of instrument is used to provide location information to a
tablet computer as the pen is moved along a magnetically sensitive
grid on a surface of the computer.

      As shown in the Figure, an inductor includes a cylindrical core
10 of magnetic core material having a longitudinal hole 12.  A single
wire 14 is formed into two to six coils 16, each of which is formed
by passing and end of the wire 14 through longitudinal hole 12 and
back in a longitudinal direction along the outer surface of core 10.
This end of the wire 14 is then wound around the outside of core 10
in a helical pattern, to form a number of coils 18.

      To form a magnetic pen, the two ends of wire 14 are connected
to the output terminals of an oscillator (not shown).  The pen is
preferably built as an untethered device, with the oscillator being
powered by a small battery.  With oscillating current flowing through
wire 14, helically-woun...