Amongst the different technologies used for touchscreens in
today’s world, there are 2 main types of touchscreens, namely the resistive
touchscreen and capacitive touchscreen. Both technologies have very different
properties, and each functions in a different manner, albeit both fulfills the
role of an interactive display output device. Due to the time constraints of
the previous seminar session by our team on Tuesday, we didn’t get the chance
to compare and contrast the both of them. However, we feel this is very
interesting and wish to share it with the class through this
blog entry. J
Resistive Touchscreen
A resistive touchscreen is made up of many layers, mainly 2
thin, electrical-resistant, transparent layers separated by a space and a surface
layer on top. When a pointy object applies pressure on the surface layer, the 2
electrical-resistant layers touch and become connected at that point. A signal containing
the position data is then sent to the CPU of the device to be interpreted. Such
a technology is usually used in restaurants, factories and hospitals because it
is highly resistant to contaminants and relatively low in cost.
Capacitive Touchscreen
A capacitive touchscreen consists of mainly an insulator
such as glass and a coat of transparent conductor such as indium tin oxide.
When an electrical conductor (such as the human finger) touches the surface of
the screen, there is a distortion in the electrostatic field of the screen,
measurable as a change in capacitance. However, different technologies (such as
surface capacitance, projected capacitance, mutual capacitance, and
self-capacitance) are used to determine the location of the touch. Such a
technology is usually used in consumer electronics, like tablet PCs and
smartphones.
Comparisons between Resistive and Capacitive Touchscreens
Properties/Features
|
Resistive touchscreen
|
Capacitive touchscreen
|
Visibility
|
Usually has good visibility indoors but poor visibility under
sunlight due to the fact that the extra layer reflects too much ambient
light.
|
Usually has very good visibility both indoors and under sunlight.
|
Touch Sensitivity
|
Pressure is required to make contact within the screen’s layers.
Fingers, fingernails, stylus or any pointy object can be used to make contact
with the screen.
|
Highly sensitive to the light touch of a finger due to the fact that
the finger is electron-rich. However, it does not respond to the touch of
other inanimate objects.
|
Accuracy and Precision
|
It is accurate to at least the resolution of the display, especially
when using a stylus. This makes it useful for handwriting recognition and
interfaces with small control elements.
|
It is accurate to only within a few pixels, but dependent on the size
of the fingertips. This makes it difficult to press something small on the
screen.
|
Cost of manufacturing
|
Cheap.
|
More expensive than resistive touchscreens.
|
Multi-touch
|
Not possible to add multi-touch functionality without re-engineering
the way resistive touchscreens are wired in a device.
|
Possible to add multi-touch functionality. Devices such as the iPhone
and the Samsung Galaxy SII are good examples of devices with this
functionality.
|
Durability
|
Top layer of the resistive touchscreen is soft, making it susceptible
to scratches and other minor damages. The screen also wears out over time and
needs to be calibrated frequently. However, since it is made of plastic, it
is more likely to withstand a fall than the capacitive touchscreen.
|
Glass is usually used as the outer layer, making it more resistant to
scratches and blemishes as compared to the resistive touchscreen. However, it
is prone to shattering when subjected to falls or impacts.
|
Hygiene
|
Since a stylus or fingernail is usually used to interact with the
screen, it has potentially less germs, fingerprints, and finger grease on the
surface of the screen.
|
Full finger touch is required to interact with the screen, meaning it
is more prone to fingerprints, finger grease, and germs. However, having a
glass surface makes it easy to clean.
|
Environmental Conditions Required
|
Works with all real world humidity levels.
|
Requires approximately 5% humidity or more for the capacitive effect
to work.
|
Nowadays many devices are using touchscreen technologies. In this blog, explained the 2 types of touchscreen technology that most of the people are using now. The two types of touchscreens are resistive and capacitive touchscreen. These 2 technologies have different properties and functions that depend on the ability of each other. We can learn in this blog the difference between the two. Resistive touchscreen has numerous layers: the electrical-resistant, transparent layer and a surface layer in the top of the screen. Each layer has functionality. You can touch in the screen and the data will send to the CPU of the device to be interpreted. Whilst the capacitive touchscreen has a glass and a coat transparent conductor such as indium tin oxide. The human finger is an electrical conductor that transmits the movement to the screen. We can see here also the table of comparison between the two touchscreen technologies. Thanks for sharing your very informative thought.
ReplyDelete