Specifications

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Physical Attributes
Aesthetics
System manufacturers considering the
inclusion of touch are understandably
concerned with aesthetics. The system must
not only meet the technological
requirements, but must also look attractive.
System Capabilities
The system designer must match the
touch system’s application considerations
with the touch system’s capabilities. Factors
to be considered include glare,
transmissivity, resolution, stylus types, and
aesthetics. For instance, systems that require
high quality graphics would gravitate
towards those touch technologies with the
best transmissivity and the least glare.
Applications requiring handwriting
recognition would need those technologies
with the highest resolution.
Another consideration would be the type
of stylus encountered in the specific
application. The touch technology selected
for the application environment must be
capable of recognizing the type of stylus
used in the application.
Most touch systems provide features
such as multiple operating and reporting
modes, improved software resolution, fault
tolerance and diagnostics. The number and
type of features required by a technology
depend on the amount of control needed by
the designer’s application. Touch systems
can be programmed to detect multiple styli,
calculate the size and center of the stylus,
reject a stylus that is larger or smaller than
the specified limits, or require that the stylus
remain in the touch-active area for a
specified amount of time before the touch is
considered a valid hit.
Another operating feature available with
some touch technologies is the capability to
report a z-axis coordinate, which measures
the amount of pressure applied to the sensor.
Typically, the harder the user presses on the
sensor, the higher the z-axis value. This z-
axis coordinate is often used to emulate the
mouse button events. This is done by
comparing the z-axis coordinate to the
threshold value.