Touch
Screens are a type of display screen that has a touch-sensitive transparent
panel covering the screen. Instead of using a pointing device such as a mouse
or light pen, you can use your finger to point directly to objects on the
screen. Although touch screens provide a natural interface for computer
novices, they are unsatisfactory for most applications because the finger is
such a relatively large object. It is impossible to point accurately to small
areas of the screen. In addition, most users find touch screens tiring to the
arms after long use.
Touch-screens are typically found on larger displays, in phones
with integrated PDA features. Most are designed to work with either your finger
or a special stylus. Tapping a specific point on the display will activate the
virtual button or feature displayed at that location on the display.Some phones
with this feature can also recognize handwriting written on the screen using a
stylus, as a way to quickly input lengthy or complex information.
A touchscreen is an input device that allows users to operate a PC
by simply touching the display screen. Touch input is suitable for a wide
variety of computing applications. A touchscreen can be used with most PC
systems as easily as other input devices such as track balls or touch pads.
Browse the links below to learn more about touch input technology and how it
can work for you.
How Do Touch Screens Work
A basic touchscreen has three main components: a
touch sensor, a controller, and a software driver. The touchscreen is an input
device, so it needs to be combined with a display and a PC or other device to
make a complete touch input system.
1. Touch Sensor
A touch screen sensor is a clear glass panel with a touch
responsive surface. The touch sensor/panel is placed over a display screen so
that the responsive area of the panel covers the viewable area of the video
screen. There are several different touch sensor technologies on the market
today, each using a different method to detect touch input. The sensor
generally has an electrical current or signal going through it and touching the
screen causes a voltage or signal change. This voltage change is used to
determine the location of the touch to the screen.
2. Controller
The controller is a small PC card that connects between the touch
sensor and the PC. It takes information from the touch sensor and translates it
into information that PC can understand. The controller is usually installed
inside the monitor for integrated monitors or it is housed in a plastic case
for external touch add-ons/overlays. The controller determines what type of
interface/connection you will need on the PC. Integrated touch monitors will
have an extra cable connection on the back for the touchscreen. Controllers are
available that can connect to a Serial/COM port (PC) or to a USB port (PC or
Macintosh). Specialized controllers are also available that work with DVD
players and other devices.
3. Software Driver
The driver is a software update for the PC system that allows the
touchscreen and computer to work together. It tells the computer's operating
system how to interpret the touch event information that is sent from the
controller. Most touch screen drivers today are a mouse-emulation type driver.
This makes touching the screen the same as clicking your mouse at the same
location on the screen. This allows the touchscreen to work with existing
software and allows new applications to be developed without the need for
touchscreen specific programming. Some equipment such as thin client terminals,
DVD players, and specialized computer systems either do not use software
drivers or they have their own built-in touch screen driver.
Touchscreens Add-ons and Integrated Touchscreen Monitors
Touchscreen add-ons are touchscreen panels that hang over an existing computer
monitor. Integrated touchscreen monitors are computer displays that have the
touchscreen built-in. Both product types work in the same way, basically as an
input device like a mouse or trackpad
Touch screens consist of a display component, typically a liquid
crystal display (LCD) or CRT covered or surrounded with a transparent sensor
device that allows the screen to detect the contact or proximity of an object.
There is a wide variety of sensor devices. Some devices are not entirely
transparent or create glare that makes the screen behind the device hard to
see. The amount of pressure or types of contact needed to detect a touch varies
from device to device. Devices also vary widely in accuracy (determining
exactly where the touch occurred), durability (reliability with repeated use or
in inclement circumstances), expected lifetime (time before failure of the
device or parts of it), and response time (how long it takes the screen to
detect a touch).
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