Posts tagged iPad

Touchscreen the omnipresent visual display is said to be the most game changer technology that allows you to operate user interface of any device by just, a single touch either using finger or stylus. Today, touchscreens is used most widely in mobiles, media players, cameras and tablets but, most of us didn’t know exactly about what is capacitive touch, Resistive touch, what’s the real difference between them and other than these, there are few more touchscreen types. Some of you might know the differences between them but, didn’t know how they work! hence this post is for everyone who wants to know everything about touchscreens.

Four kind of touchscreens are widely used among different applicable areas.

• Resistive – basic touch mobiles, low cost touch devices for eg – Nokia N900, Nokia C6, HTC Tatoo, Samsung Omnia Pro, LG Cookie.
• Capacitive – Tablets, High-end Smartphones, High-end touch devices  for eg – Apple iPhone, Nokia N8, Motorola Milestone, LG Optimus One, Samsung Wave I & II.
• Surface Acoustic Wave (SAW) – harsh Environment, food Preparation, avionics.
• Infrared - outdoor applications, ATM & bill pay kiosks, DVD rental kiosks, point of sale.

These technologies differ in the mechanisms they use and their processes for enabling touchscreen technology. For instance, a capacitive touch panel works with an electric field, surface acoustic wave uses ultrasonic waves, infrared uses light beams.

Difference between all of them

Let’s talk briefly about each of them:

What is Resistive Touchscreen and how it works?

Resistive touchscreen are made up of many layers but, the most crucial are two two flexible layers coated with a resistive material and gap between these layers is separated either by an air gap or microdots. Once we apply a bit pressure to touch the surface of touchscreen, it creates a contact between both of the layers while, the horizontal and vertical lines on both of the layers records the actual location of the precise touch. Resistive touch is a primitive and it was widely used in touch smartphones but, now it’s been replaced by capacitive touch. Well that doesn’t means resistive touch is dead as it’s still used in making low-cost touch mobiles as they are cheap.

Advantages

• Low-cost, water and dust resistant
• Touch from any object, either finger, Stylus etc

Disadvantages

• Can’t determine two-touch made simultaneously ( No multitouch)
• Allows only 85% of the light let out emitted by the display
• Easily scratched and couldn’t used with sharp objects.
• The touch error rate is high

What is capacitive touchscreen and how it works?

Next is capacitive touchscreen, which are comprises of an insulator such as glass, coated with transparent conductor such as indium tin oxide. When we touch the, surface of the touchscreen it results in a distortion of the screen’s electrostatic field, which is measured as a change in capacitance. The touch location than sent to the controller for processing. Today, capacitive is the most preffered choice amongst device makers and is widely used in devices such as tablets, Smartphones, MP3 players, computer monitors etc.

Advantages

• Multi-touch capable
• Better clarity and allows upto 90% transparency.
• Fast and accurate response in comparable to resistive
• Long-life around 225 million clicks

Disadvantages

• Sensitive only to conductive object like finger, no stylus support. However, stylus with conductive material on it’s tip can work
• Cannot be used in all weather scenarios

What is Surface acoustic Wave Touchscreen and how it works?

Surface acoustic Wave (SAW) is a more advanced kind of touchscreen and uses ultrasonic waves that pass over the touch screen panel. When the screen is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for processing. Because the panel is all glass there are no layers that can be worn, giving this technology the highest durability factor and also the highest clarity.

Advantages

• Being no electric field created, it emits 100% light resultantly quality image received.
• Operated by a finger, gloved hand, or soft tip stylus
• Durable glass construction and long life
• Fast response time

Disadvantages

• Moving liquids or condensation can cause false touches
• They are expensive
• They can be easily damaged
• Doesn’t support drag or draw effectively

What is Infrared Touchscreen and how it works?

An infrared touchscreen uses an array of X-Y infrared LED and photo detector pairs around the edges of the screen to detect a disruption in the pattern of LED beams. These LED beams cross each other in vertical and horizontal patterns. This helps the sensors pick up the exact location of the touch. When a user touch the surface of screen, the infrared emitted from LED beam is broken, the absence of the signal at the collector is detected and receiver transmits X-Y axis information to the PC port via touch controller.

Advantages

• Clear as glass. TIhe clarity of the technology improves readability at a glance
• Can detect essentially any input including a finger, gloved finger, stylus or pen
• Doesn’t require any patterning on the glass which increases durability.
• Comprehensive adaptability can resists any interference from current, voltage or static

Disadvantages

• Since the infrared beams are a little in front of the display, touch is activated even before the user actually touches the display, causing parallax errors
• Infrared touchscreens are also expensive .
• Comparatively Low response time

Now we hope that after reading this What is it you must have cleared your each and every doubts about touchscreens and from the next time when you purchase a new smartphone, tablet, touch device etc you can easily choose the perfect one for you. Do you like this post share it with your friend and don’t forget to add your comments below. Lastly, if you found any correction or wrong information, than please inform us using comments and we’ll be happy to make them correct.

Image Credits PC Pro, Planar, Google Image Search

Source Wikipedia, Planar, Ausun International, Tathya.net