Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Mercury Switch with Built-in Hysterisis for Pen-Based Computers

IP.com Disclosure Number: IPCOM000106681D
Original Publication Date: 1993-Dec-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 4 page(s) / 96K

Publishing Venue

IBM

Related People

LeFranc, E: AUTHOR [+3]

Abstract

Described is a hardware implementation for stylus operated pen-based computers. The implementation incorporates a mercury switch with built-in hysterisis so as to eliminate erroneous screen activation and improved user operation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Mercury Switch with Built-in Hysterisis for Pen-Based Computers

      Described is a hardware implementation for stylus operated
pen-based computers.  The implementation incorporates a mercury
switch with built-in hysterisis so as to eliminate erroneous screen
activation and improved user operation.

        Typically, pen based computers employ a touch screen which
operates in conjunction with a stylus, for 'pen mode, as well as
finger touch, for 'touch mode' when entering data.  However,
difficulties can be encountered when users switch from 'touch mode'
to 'pen mode'.  During 'touch mode' data entry is performed, as in
capacitive type touch screens, by touching the screen with a finger
so as to discharge the area being touched.  The application software
then knows what part of the screen has been discharged through the
use of x,y coordinates and thereby knows the action to be performed.
In 'pen mode', the screen should be immune to a finger touch and
should respond only when the pen makes contact with the screen.

      In prior art, several methods of switching between 'touch mode'
and 'pen mode' have been used, such as utilization of a switch at the
tip of the stylus.  When the stylus is positioned at the screen, the
switch is depressed by the user and the computer is activated into
'pen mode'.  However, with this approach, any touch input prior to
actually making contact on the screen with the stylus can be
interpreted by the computer as a command.  In order to avoid
inadvertent commands, the user must be trained to ensure that the
screen is touched first by the stylus in order to avoid activating
the screen with a finger touch.

      Another prior art method of switching was to use a mechanical
switch placed on the side of the stylus such that when the switch is
pressed the computer will know whether the stylus is in 'pen mode' or
'touch mode'.  However, this approach requires the user to
consciously press a button before going into the various modes.
Another approach was the use of a proximity switch placed at the tip
of the stylus.  Although this method solved the problem of
instructing the screen to go into the proper mode as soon as the
stylus was close to the screen, this method presented user with
problems.  For example, if the user held the stylus and put a finger
onto the screen before the stylus is close enough...