Components of Laptop Displays | CompTIA A+ 220-1001 | 1.2

In this video you will learn about the components within the display of a laptop such as:  various types of laptop displays, WiFi antenna connectors/placement, webcam, microphone, inverter, & the digitizer/touchscreen.

The display of a laptop is often simply referred to as the screen.  There are a variety of different types of screens and components behind the glass in order to make the screen work.  In the following sections we will discuss the essential components of a laptop screen technology.

LCD

A liquid crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers.  Liquid crystals do not emit light directly, instead it uses a backlight or reflector to produce images in color or monochrome.  An LCD is made with either a passive or active-matrix display grid.  Active-matrix is considered the better technology, and is the type used in the vast majority of current laptops.  An active-matrix screen uses a transistor for every dot onscreen.  For example:  1,600×900 active-matrix LCD screen has 1,440,000 transistors.  Each pixel intersection in an active-matrix screen has a transistor, and a small current is sent across the screen grid.  The transistors can manage the current on the screen very quickly, giving the user an experience of smoothly flowing motion.

Advantages of LCD

• No radiation emission from screen
• Perform better under brighter conditions because of anti-glare technology
• Not affected by the increase or decrease in air pressure
• Lighter in weight with respect to screen size
• Images appear with greater resolution
• Colors of images look more realistic
• Low power consumption

Disadvantages of LCD

• More expensive compared to a plasma TV of the same size
• Less picture quality when viewed on the side or at an angle
• There is motion delay for fast-moving images
• The aspect ratio & resolution are fixed
• Not proficient at producing black and very dark grays due to being back-lit
• In a “standard configuration” they are not appropriate for use in dimly lit & dark conditions
• LCDs are fragile:  touching an LCD screen with your fingers can possibly leave pressure marks that may forever mar the display

OLED

An organic light-emitting diode (OLED or organic LED), also known as an organic EL (organic electroluminescent) diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current.  An OLED display uses a layer of organic compounds between two electrodes to emit light which allows for the brightness of each OLED pixel to be individually controlled.  OLED displays have been developed in two forms:  passive matrix (PMOLED) and active matrix (AMOLED).

Advantages of OLED

• Brighter:  OLEDs can be larger than other types of screens & offer higher resolutions.
• Thinner in Size & Lighter in Weight:  OLEDs are a good choice for smartphones, tablets & convertible (two-in-one) units that switch between laptop & tablet modes.
• Energy Efficient:  Only the lit pixels draw power; with good application design, this can greatly extend battery life.
• Faster Refresh Rates:  OLEDs can refresh quickly, which makes them a favorite of gamers who value quick response time.

Disadvantages of OLED

• Expensive
• Color degradation is possible due to relying upon organic materials to produce light
  • Can affect brightness & color balance
• Burn-in:  when a static image for a prolonged period of time is left on screen, it can cause a permanent “scar” to be displayed

WiFi Antenna Connector/Placement

In the base of the laptop is where the miniPCIe card that contains the WiFi radio is located. The WiFi antenna is usually a part of the overall screen assembly.  If a laptop screen is damaged, the WiFi antennas are at risk of also being damaged.  In an OLED display, the inverter is not present, but the rest of the components are in the same locations.

Webcam

Webcams typically come standard in most modern laptops. Almost all built-in webcams are at the top-center edge of the display assembly.  If you need a higher-resolution webcam, you can use an external webcam that plugs into a USB port.

Microphone

Most laptop microphones are also built into the display assembly which are used by the webcam or for other recording purposes.  If you need a higher-quality microphone, you can use a microphone as part of a headset that plugs into an audio port or a USB port.

Inverter

An inverter is a pen-sized board that is usually placed on the bottom of the LCD screen, either in the same case with the LCD screen, or above the keyboard.  The inverter is one of the key parts within a display; it allows for the laptop’s display to be lit by providing power to the screen’s backlight.  If the laptop’s inverter or backlight fails, the laptop display will become so dim that it is almost impossible to use.  The inverter is a power converter that changes low-voltage DC power into the higher-voltage AC power needed to power a CCFL (cold cathode fluorescent lamp) backlight.  If the inverter fails, there is no power to run the backlight.

Digitizer/Touchscreen

A digitizer is a hardware device that receives analog information, such as sound or light, and records it digitally.  Usually the information is stored in a file on a computing device.  This process is called digitization.  Touchscreen displays use a digitizer layer on top of the display panel.  The digitizer detects and transmits touches to the laptop processor.  Digitizers are also used on touchscreen smartphones, tablets, fitness monitors, smart watches, phablets, e-readers, & smart cameras.