1.2 Laptop Displays

Liquid crystal display (LCD)

Advantages

• Light shines through liquid crystals

• Lightweight

• Relatively low power

• Relatively inexpensive

Disadvantages

• Black levels are a challenge

• Requires separate backlight

  • Florescent, LED, etc

  • Lights are difficult to replace

Twisted Nematic (TN) LCD

• Original LCD technology

• Fast response times

• Poor viewing angles - Color shifts

In Plane Switching (IPS) LCD

• Excellent color representation

• More expensive to produce than TN

Vertical Alignment (VA) LCD

• A good compromise between TN and IPS

• Good color representation

• Slower response times than TN

Organic Light Emitting Diode (OLED)

• Organic compound emits light when receiving an electric current

• Thinner and lighter

  • flexible and mobile-no glass needed

• No backlight

  • Organic compound provides the light

Cold Cathode Fluorescent Lamp (CCFL)

• Higher voltage and power needed

• Added thickness to the display

• No longer a common backlight

• Older laptops will use these

LED backlit LCD display

• Backlit is LEDs instead of fluorescent

• LEDs around the edge of the screen

• An array of LEDs behind the screen

• The latest laptops are LED-backlit

Backlight

• LCD displays needs this

• Florescent Lamp

• LED to LCD display to your eyes

Inverter

• Some laptops have these

• Turn DC to AC

Steps to verify backlight

1. Look closely at the

2. Use a flashlight

   • if display is visible with flashlight, backlight is out

3. May need to replace the LCD inverter or display

Digitizer

• use a pen-like device as input

• Stylus input

• Useful for graphical input

• Used commonly on laptop/tablets

Touchscreen

• Digitizer responds to touch

• No keyboard required

• Often still available

• Many options for input