Displays
Displays are commonly Liquid Crystal Displays, wherein back light shines through liquid crystals.
LCD Advantages:
- Lightweight
- Relatively low power
- Inexpensive
LCD Disadvantages:
- Because back light must shine through, true black is a challenge
- Requires a separate back light
- Florescent, LED, etc.
- Lights are difficult to replace
Types of LCD displays:
| Type | Advantages | Disadvantages |
|---|---|---|
| Twisted Nematic (TN) | Fast response times | Poor viewing angles (color shifts) |
| In Plane Switching (IPS) | Excellent colour representation | More expensive than TN |
| Vertical Alignment (VA) | Decent colour representation | Slower than TN |
Overall, the compromise option is the VA monitor.
Organic Light Emetting Diode (OLED)
OLED displays use organic compounds that emit light when provided with current (and therefore have no backlight). As a result, they are thinner and lighter, providing more flexibility and mobility since they do not require glass (no liquid crystals.
These are often on tablets, phones, and smart watches due to high colour representation, and due to the higher cost over LCD screens (making them more affordable in smaller sizes).
Fluorescent vs LED
LEDs require a back-light of some kind. Older laptops will use fluorescent lights known as Cold Cathode Fluorescent Lamps (CCFL).
CCFLs have the following properties:
- higher voltage and power needed
- added thickness to the display
They are not very common anymore, however, since they are replaced by LEDs.
The LED set-up has lights either along the edge of the display or in a matrix accross the display itself. This is the case for newer computers, and so common that people refer to them as “LED displays”, though they really mean “LED-backlit LCD”.
Backlight and inverter
CCFL displays will also often include inverters in the display, since CCFL bulbs require AC power while laptops use DC power.
In the case of a display that is blank, we can shine a flashlight into the display to try and see if we can notice faint information. This would suggest the display is functional, but the back-lighting is not. In this scenario, only the inverter might need replacement, rather than the entire array; other times the display may need replacement.
Antennas
The wireless antennas of a laptop are often routed to the top of the monitor casing, since that is the highest point of a laptop (WiFi main and aux, as well as Bluetooth antennae).
This creates challenges when replacing displays, since those have to be connected as well.
Usually, the 802.11 antenna cables will be a black and a white cable.