Laptop Displays 1.2

Portable LCD

• Liquid crystal display

– Light shines through liquid crystals

• Advantages

– Lightweight

– Relatively low power – Relatively inexpensive

• Disadvantages

– Black levels are a challenge – Requires separate backlight – Florescent, LED, etc.

– Lights are difficult to replace

LCD technologies

• TN (Twisted Nematic) LCD

– The original LCD technology

– Fast response times (gaming!)

– Poor viewing angles - color shifts

• IPS (In Plane Switching) LCD

– Excellent color representation

– More expensive to produce than TN

• VA (Vertical Alignment) LCD

– A good compromise between TN and IPS – Good color representation

– Slower response times than TN

OLED

• Organic Light Emitting Diode

– Organic compound emits light when

receiving an electric current

• Thinner and lighter

– Flexible and mobile - no glass needed

• No backlight

– The organic compound provides the light

• Tablets, phones, smart watches

– Very accurate color representation – A bit higher cost than LCD

Wi-Fi antennas

• Multiple antennas

– WiFi main and aux / Bluetooth

• Antenna wires wrap around the laptop screen – It’s up high!

Near-field communication (NFC)

• Short-distance networking

– 4 centimeters or less

– Data transfers or authentication

• Common on mobile phones and smart watches – Payment method on your wrist

• Use it for authentication without typing a password – Hospital workstations, warehouses, manufacturing

Webcam

• Video capture - Built-in camera and microphone

• Usually includes both audio and video – Specialized drivers and software

Microphone

• Built-in to the laptop display – Useful for video calls

• Not good for non-casual use

– Analog or USB microphones can help

Fluorescent vs. LED backlighting

• LED-backlit LCD display

– Backlight is LEDs instead of florescent – LEDs around the edge of the screen

– An array of LEDs behind the screen

– The latest laptops are LED-backlit

• CCFL - Cold Cathode

– Fluorescent Lamp

– Higher voltage and power needed – Added thickness to the display

– No longer a common backlight

– Older laptops will use these

Backlight and inverter

• LCD displays need a backlight

– Florescent lamp/LED to LCD display to your eyes

• Some laptops have inverters - Turn DC into AC

• Verify backlight

– Look closely and use a flashlight

• May need to replace the LCD inverter or display – Choose carefully

Digitizer

• Use a pen-like device as input

– Stylus input - Useful for graphical input

• Used commonly on laptop / tablets – Or hybrid devices

Touchscreen

• Merge laptop and tablet input

– Digitizer responds to touch - No keyboard required

• But often still available

– Many options for input - Use the best one for the job