LCD
LCD stands for Liquid Crystal Display. The majority of laptops today use LCD displays.
A backlight shines through liquid crystals, color filters, and other components to display the text and images on your screen. Liquid crystals can either pass or block the backlight when a charge is applied. The liquid crystals are enclosed between two thin glass layers. There is also a red/green/blue transparent film in the front which creates the colorization.
Advantages of LCD
- Lightweight
- Doesn’t consume a lot of power
- Relatively inexpensive
Disadvantages of LCD
- Doesn’t produce true black colors
- LCDs use a backlight such as Florescent or LED bulb which can be difficult to replace
Fluorescent vs LED backlights
LCD displays use either a Fluorescent or LED backlights to shine through the the liquid crystal display.
When LEDs are used to backlight an LCD display, the display is often called an LED display. LED stands for Light-Emitting Diode. LEDs are basically semiconductors that convert electricity into light without producing much heat. LEDs are usually placed around the edge of the screen or in a matrix pattern. LEDs use the same DC voltage that’s available in the laptop so it doesn’t have to do any voltage conversion.
Some older laptops use Fluorescent lights as backlighting. Fluorescent backlighting is called CCFL (Cold Cathode Flourescent Lamps). CCFL runs on AC power. When a display is backlit with CCFL it is called an LCD display. CCFL requires higher voltage and more power than LED. CCFL displays are also a little thicker than LED displays.
There are 3 common types of LCD Displays:
- TN (Twisted Nematic) which provides high refresh rates and are inexpensive, but offer poor viewing angles.
- IPS (In-Plane Switching) provides better viewing angles and color but have slower response times.
- VA (Vertical Alignment) offers the best aspects of both TN and IPS.
LEDs are more efficient and have longer lives than CCFL.
OLED
OLED stands for Organic Light Emitting Diode.
OLED displays are made up of organic compounds that emit light when electric currents are provided.
Due to their high costs, OLED displays are more common in smaller devices like phones, smart watches, and tablets versus laptop displays.
Advantages of OLED
- Thinner, lighter, and more flexible
- No backlight required so it provides a better color representation and can achieve true black.
Disadvantages of OLED
- Susceptible to burn in
- Organic materials degrade over time
- More expensive than LCD
- Consumes more power than LCD
Replacing the Display
If the display goes black, verify if the backlight is the issue. To do this use a flashlight to shine on the display and see if you can see the information on screen. If you can still see information this indicates that there’s an issue with the backlight and it’s not lighting up the information. In this case, you’ll need to replace the entire display or the issue may also be the inverter if it’s a CCFL backlight.
