Like other tablet devices, the iPad relies on a specially designed touch screen for user input. The screen allows you to activate programs and enter data by typing on a virtual keyboard, touching programs on the screen and making certain types of gestures. Understanding the capabilities of the iPad touch screen helps you get the most use out of your hardware.
The iPad screen is a 9.7-inch LCD display protected by a scratch-resistant sheet of glass. Apple coats this screen with an oleophobic substance designed to repel the oils left by your fingertips, allowing you to wipe the screen clean easily. The key to the screen is a thin layer of capacitive material embedded in the surface that serves as the heart of the iPad input system. The material is transparent to the user, but it allows the system to detect a touch anywhere on the surface of the screen.
Capacitive Touch Screens
Early touch screens relied on pressure, forcing users to depress the screen to connect two layers of conductive material to signal a touch. Capacitive screens work by constantly monitoring the electrical field of the screen. Since your body conducts electricity, touching the screen alters this field, and the system can detect that change and use it to determine where you touched. The iPad screen also features multi-touch technology, which allows the system to interpret multiple contacts, such as those when you zoom pictures by pinching or moving your fingers apart.
The advantage of the capacitive design is in the ease of use. The reduction in the amount of force needed to signal a touch means less wear and tear on the screen and increased comfort for users. In addition, the capacitive display can detect contacts even through certain types of screen protectors, allowing you to add a layer of protection to your iPad’s screen without significantly reducing its sensitivity.
The primary disadvantage of the capacitive screen is that it requires direct skin contact or a similar alteration in the screen’s electrical field to function. Most styluses do not register on the iPad’s screen, and you cannot use the device while wearing gloves. There are third-party solutions to this problem, as some manufacturers make conductive styluses that transmit your body’s electrical field to the device, and sewing a small piece of conductive thread into the fingertips of winter gloves allows you to use your iPad without sacrificing warmth on a cold day.