2.01 Compare and contrast the display components of mobile devices
Introduction
Mobile devices, like smartphones and tablets, are compact and portable, providing powerful computing on the go. Unlike desktops or laptops, they're designed for mobility with touch interfaces and wireless connectivity. These devices have unique hardware and maintenance needs. In this section, we'll cover one of the key components of these devices, the display.
Display Types
One of the most common components to require repair on a mobile device is the display. For mobile devices to be truly portable, their design integrates system components like the CPU, RAM, storage, and networking within the device chassis, using a touch screen display for both input and output.
Liquid Crystal Displays (LCDs): Most mobile screens are based on LCD technology, where liquid crystals change properties with applied voltage to display images. Each pixel consists of subpixels with red, green, and blue (RGB) filters. These are controlled by transistors on a thin film transistor (TFT) panel.
Twisted Nematic (TN): Uses crystals that twist or untwist in response to voltage, offering fast response times to reduce motion blur but with limited color accuracy and narrow viewing angles.
In-Plane Switching (IPS): Uses rotating crystals to provide better color reproduction and wide 178/178-degree viewing angles, ideal for graphics and design work, though early models had slower response times.
The three main types of TFT LCDs are:
Vertical Alignment (VA): Uses crystals that tilt to offer a wide color gamut and high contrast ratios-the comparison between the luminance of the brightest white and the darkest black displayed- (up to 3000:1), better than IPS but with less favorable viewing angles and slower response times, leading to potential motion blur.
LED Backlit Displays: LCD screens need illumination, which is provided by LED arrays, often edge-lit with a diffuser for even brightness. Older laptops used cold cathode fluorescent (CCFL) bulbs with an inverter for backlighting, but this technology is now outdated.
Organic LED (OLED) Displays: OLEDs, or AMOLEDs, use organic compounds that emit light per pixel, eliminating the need for a backlight. This provides excellent contrast ratios, thinner and lighter displays, and lower power consumption. OLEDs can also be made from flexible materials, allowing for curved or rollable screens. However, they may have lower brightness levels under direct sunlight and are more susceptible to burn-in, where static images can leave permanent marks on the display.
By understanding these display technologies, you can better appreciate how mobile devices balance factors like color accuracy, viewing angles, brightness, power efficiency, and durability to enhance the user experience.
A mobile device's display is composed of multiple layers, each with specific functions that contribute to the overall screen experience.
Digitizer Functions: The digitizer layer, located between the protective glass and the display panel, converts analog touch inputs into digital signals. It detects touch through a grid of sensors and sends this information via a digitizer cable to a circuit that translates it into digital commands.
Modern devices use capacitive digitizers that support multitouch gestures like "pinching" and "swiping," enhancing user interaction. Newer devices may also include haptic feedback to simulate tactile sensations, making touch inputs feel more realistic.
Screen Protection: The topmost layer of the display is made from scratch-resistant and shock-resistant tempered glass, such as Gorilla Glass, to protect the screen from damage. Some users add an extra screen protector to safeguard against scratches and impacts, which must be applied carefully to avoid interfering with touch sensitivity.
Rotating and Removable Screens: Mobile devices are designed to work in both portrait and landscape modes, with accelerometers and gyroscopes detecting changes in orientation to automatically adjust the display. These sensors also enable other functionalities, such as turning the device into a steering wheel in driving games.
Some devices, like hybrid tablets or laptops, allow the screen to be rotated, flipped, or even detached from the keyboard, providing flexible usage options as both a laptop and a tablet.
Understanding these components helps in appreciating how mobile displays provide interactive and versatile user experiences.
Summary
Great job completing this lesson on mobile device display types! You've learned about the various display technologies—like LCD, LED, and OLED—that make mobile screens vivid and responsive, each offering different benefits in color accuracy, viewing angles, and power efficiency. You also explored the key components of a display, including digitizers for touch input, protective layers, and sensors for screen rotation and orientation. With this knowledge, you're now better equipped to understand the repair and upgrade options for mobile displays. Keep up the good work as you move on to the next lesson!