What’s the best type of touchscreen in terms of iPad?

  The iPad is the most popular tablet in the world, and for good reason. The introduction of the iPad in 2010 virtually defined the market. It wasn't the first tablet ever, but it was the first tablet people wanted to buy.  Since 2010, it has been the flagship of tablets. But it's not perfect. If you are looking to buy a tablet, it's important to study both the pros of an iPad and the areas where it doesn't quite shine as brightly as the competition. I’m going to deal with a topic that’s sparked more than a dozen emails recently. In this article, let’s discuss the best type of touchscreen.

  Capacitive screens generally receive more favorable reviews than resistive, but I’ve seen some strong views in the other direction on various blogs and online forums, with people saying that resistive screens are more accurate. I’d appreciate your views on which screen technology to choose.” One of readers mentioned.

  The front surface is made of scratch-resistant, flexible plastic with a thin film of conductive material (usually Indium Tin Oxide or ITO) printed onto its underside. Beneath it is a second layer – usually made of glass, but sometimes of hard plastic – also with a coating of ITO. The two layers are kept apart by tiny bumps or spacers placed at regular intervals, and the thin layers of ITO create an appreciable electrical resistance – the sandwich is so constructed that electrical charge runs from top to bottom on one layer but side-to-side on the other layer.

  When the screen is touched the plastic deforms so that the two ITO films meet, and by measuring the resistance of both layers at their point of contact it’s possible to get an accurate measurement of the touch position. This, of course, relies on an even coating of ITO on the layers, plus accurate calibration: with some early touchscreen mobiles, the calibration could drift as the battery became depleted, but nowadays, unless you buy a fake phone, you shouldn’t experience this problem.

 

  Most older phones use resistive screens, but that isn’t to say it’s an out-of-date technology, as phones are still being churned out using this type of screen (a good clue is normally, although not always, that the device is supplied with a stylus). Most people probably first encounter resistive screens in Windows Mobile devices.

  There are two types of capacitive touchscreen generally available, surface and projected, and it’s the latter that you’ll find in smartphones. These again consist of a sandwich, but this time of two spaced layers of glass, again coated with ITO on the inside. Depending on the particular screen, the ITO layer may be a uniform coat, a grid, or parallel stripes running at right angles on the two sheets. The latter scheme is used in the iPhone and the iPod Touch Duplo, better known as the iPad. Think back to O level physics, and you might remember that a capacitor consists of two plates separated by an insulating material, which may of course be air. Now picture those perpendicular stripes on two glass plates – wherever a stripe crosses one below it forms a capacitor so small it’s measured in femtofarads (10-15F).

  This small size is both bad news and good: bad, because such a tiny capacitance is difficult to measure and requires complex filtering to eliminate noise; good, because given such a small capacitance it isn’t just the gap between the “plates” that affects the capacitance but also the space around them. As your finger comes close to a capacitor it changes the local electrostatic field, and the system constantly monitors each tiny capacitor to discover exactly where the finger touched the screen: because the measurement points are discrete, it’s possible to tell whether several fingers are all touching the screen at once, unlike with a resistive unit.

  So what’s the difference between these two technologies in practice? First and foremost, resistive screens tend to be stylus-friendly, while capacitive screens favor a swipe with a finger. That’s a generalization, because some manufacturers have recently made resistive screens that are more finger-friendly, while some clever people have come up with conductive styluses that can work (kind of) on capacitive screens. For finger-based user interfaces capacitive is still far better, though, while if you need the single-pixel accuracy of a stylus then resistive is the sensible choice.

  The fact capacitive screens can sense more than one finger press at a time brings me to their major advantage – they can support multitouch interfaces. For those of you who’ve never used such an interface, I can best describe it as one of those light-bulb-over-head revelations. The classic demonstration is in Google Maps, where if you want to zoom in on an area you simply make a pinching gesture on the screen and the map zooms proportionally: spread fingers outwards to zoom in the other direction.

  One area where resistive screens win out is on price, since capacitive screens (plus their associated controller chips and other trimmings) usually cost around half as much again as their resistive counterparts. This isn’t too significant in a high-end smartphone where the margins tend to be pretty large, but it becomes an issue for entry-level devices. Here, a website can offer you high-quality iPad 2 touch screen digitizer replacement as the original one. Our products are tested strictly and have the quality warranty as well.