The Apple iPhone is different -- many of the elements of its multi-touch user interface require you to touch multiple points on the screen simultaneously. For example, you can zoom in to Web pages or pictures by placing your thumb and finger on the screen and spreading them apart.
To zoom back out, you can pinch your thumb and finger together. The iPhone's touch screen is able to respond to both touch points and their movements simultaneously. We'll look at exactly how the iPhone does this in the next section. Sign up for our Newsletter! Mobile Newsletter banner close. Mobile Newsletter chat close. Mobile Newsletter chat dots.
Mobile Newsletter chat avatar. Mobile Newsletter chat subscribe. Prev NEXT. Cell Phones. Place two fingers on the screen and spread them apart. This action allows you to see a close-up of items on the screen. Pinch open quickly to immediately increase the page size to percent.
If you want an in-between size, pinch open more slowly. An indicator displays the current page magnification as you pinch. Place two fingers on the screen and bring them together. This action allows you to see more items on the screen.
Pinch closed quickly to immediately reduce the page. Tap Using one finger, quickly and firmly touch the screen, then lift your finger. In , Apple released one of the first touchscreen devices , the ill-fated Newton PDA, that came complete with, in theory, handwriting recognition.
But touchscreen's 'Golden Age' arguably started with the release of the first iPhone in As it turns out there are actually several different methods of producing touchscreens. Each one is incredibly ingenious with the only real commonality between them being the end result - a touchable screen. Resistive touchscreens are by far the most common and they are also one of the simplest, technologically-wise types. Consisting of three main layers, these touchscreens take advantage of electrical resistance to work.
The uppermost layer consists of flexible conductive polyester plastic. This sits on top of a layer of conductive glass with a layer of insulating membrane sandwiched between the two. When you press your finger down on the polyester layer, you force it to depress and touch the glass layer below. This completes an electrical circuit; much like pressing a key on a keyboard. A control chip connected to the screen then determines the coordinates of the place you touched.
Simple yet effective. Capacitive touchscreens are one of the oldest solutions and were invented by E. Johnson back in the s. These types of the touchscreen are composed of two layers of conductive glass that are separated by an insulator -- just like a regular capacitor. When your finger approaches the screen, it disrupts the electrical field by a certain amount depending on where your finger is. The position can then be determined using a set of sensors to detect the decrease in electrical current at the point of contact.
Unlike other touchscreens, capacitive ones can actually be touched in multiple locations simultaneously. They also cannot be used with a plastic stylus, as plastic is an electrical insulator.
Similar to traditional conductive touchscreens, projected capacitive touchscreens have some advantages over their rivals. One of the main pros is that they can be used when the operator is using surgical gloves or thin cotton gloves.
These touchscreens consist of a sheet of glass with embedded transparent electrode films and an IC chip.
This setup creates a 3D electrostatic field just above the screen -- hence the name. A touchpoint is then detected.
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