Laptop Displays - CompTIA A+ 220-1101 - 1.2

Summary

This script delves into the technology behind LCD displays in laptops, highlighting advantages like lightweight design and low power consumption. It discusses various LCD types, including TN for fast response times, IPS for color accuracy, and VA as a balanced option. OLED displays are also introduced for their thinness and light-emitting properties. The script touches on the integration of wireless antennas in laptop displays and the importance of correctly reconnecting them during display replacement. It also covers the evolution from CCFL to LED backlighting and the role of digitizers in touchscreens, providing a comprehensive overview of laptop display technology.

Takeaways

• 💡 LCD displays are widely used in laptops due to their lightweight, low power consumption, and cost-effectiveness.
• 🔦 LCD screens can struggle to achieve true black colors because the backlight must shine through the liquid crystals.
• 🛠️ Repairing or replacing an LCD display can be challenging due to the integrated backlight being part of the display itself.
• 🎮 TN (Twisted Nematic) LCDs offer fast response times, making them suitable for gaming and fast-paced graphics applications.
• 🎨 IPS (In Plane Switching) LCDs provide superior color representation, ideal for graphic design and desktop publishing.
• 🖥️ VA (Vertical Alignment) LCDs are a middle ground, offering good color representation but with slower response times than TN displays.
• 📱 OLED (Organic Light Emitting Diode) displays are thin and light, as they do not require a backlight or liquid crystals, and are commonly used in modern devices.
• 📡 Laptop displays often incorporate wireless antennas, which can complicate the replacement process due to the need to reconnect antenna wires.
• 🔧 Replacing a display on an older laptop might involve dealing with CCFL backlights and inverters, which convert DC power to AC for the backlight.
• 🖌️ Hybrid devices with stylus input often include a digitizer that converts analog input into digital signals for precise control.
• ✍️ Touch screen digitizers allow for input through finger touch, converting it into a digital form that can be used by the system.

Q & A

What is an LCD display and how does it work?

An LCD display, or liquid crystal display, is a technology that uses liquid crystals associated with color filters and a backlight to produce images on a screen. The backlight shines through the liquid crystals to display the image.

What are the advantages of using LCD displays in laptops?

LCD displays are advantageous for laptops because they are lightweight, consume very little power, and are relatively inexpensive to manufacture, which helps keep the cost of laptops down.

What are some disadvantages of LCD displays?

Disadvantages of LCD displays include difficulty in achieving true black colors due to the need for a backlight to shine through, and potential issues with the backlight itself, which can be challenging to repair or replace if it fails.

What is the difference between TN, IPS, and VA LCD technologies?

TN (Twisted Nematic) LCDs offer fast response times but have poor viewing angles. IPS (In Plane Switching) LCDs provide excellent color representation, making them ideal for graphic work, but are more expensive. VA (Vertical Alignment) LCDs are a compromise, offering good color representation with slower response times than TN.

Why are OLED displays becoming more popular in devices like tablets and smartphones?

OLED displays, or Organic Light Emitting Diodes, are popular because they do not require a backlight, allowing them to be very thin and lightweight. They provide great color representation and are easy to integrate into portable devices.

How are wireless antennas integrated into laptop displays?

The display of a laptop is the highest component in the system, making it an ideal place for wireless antennas. Antennas for 802.11, Bluetooth, and other wireless technologies often run to the top of the laptop display.

What challenges are there when replacing a laptop display that includes wireless antennas?

When replacing a laptop display, one must ensure to reconnect all video components and antenna wires correctly to avoid losing wireless functionality. This requires careful attention to the original wiring path.

Why are webcams often integrated into laptop displays?

Webcams are integrated into laptop displays for convenience, allowing for easy video capture and participation in video conference calls without the need for external devices.

What is the difference between CCFL and LED backlights in LCD displays?

CCFL (Cold Cathode Fluorescent Lamp) backlights require more power and space compared to LED backlights. LED backlights are more energy-efficient, thinner, and are either edge-lit or in a matrix behind the display, providing better control over lighting.

What is the function of inverters in older laptops with CCFL backlights?

In older laptops with CCFL backlights, inverters convert DC power from the laptop to AC power needed to power the fluorescent backlights.

How can you tell if the backlight of an LCD display has failed?

If you can make out information on the screen when shining a flashlight directly at it, the problem might be with the backlight rather than the display itself. This could indicate a need to replace the inverters or the entire display, depending on the laptop model.

What is a digitizer and how does it relate to stylus and touchscreen inputs on a device?

A digitizer is a component within a display that converts analog input from a stylus or touchscreen into digital signals that the computer can process. This allows for precise input methods like drawing directly on the screen or using touch gestures.

Outlines

00:00

💻 LCD Displays and Laptop Technology

The paragraph discusses the technology behind LCD displays in laptops, highlighting their advantages such as being lightweight, power-efficient, and cost-effective. It also covers the disadvantages, including the difficulty in achieving true black and the potential issues with different types of backlights like fluorescent or LED. The paragraph introduces three LCD technologies: TN for fast response times, IPS for better color representation, and VA as a middle ground. It also touches on OLED displays, which are thin and light due to the absence of backlights and liquid crystals. Additionally, it mentions the integration of wireless antennas into laptop displays and the challenges in repairing or replacing them, especially when dealing with webcams and their associated wiring.

05:02

🌐 Backlighting and Display Inputs in Laptops

This paragraph delves into the specifics of backlighting in older and newer laptop displays, contrasting CCFL (Cold Cathode Fluorescent Lamp) with the more modern LED backlights. It explains the role of inverters in powering CCFL backlights and provides a method to diagnose backlight failure. The paragraph also explores the use of high-resolution displays in hybrid devices, the function of styluses with digitizers, and the conversion of analog inputs into digital signals. It concludes by discussing the versatility of input methods in modern devices, which can include keyboards, styluses, and touchscreens.

Keywords

💡LCD Display

LCD, or Liquid Crystal Display, is a flat-panel display technology that uses liquid crystals to control the passage of light. In the context of the video, LCD displays are described as being lightweight, power-efficient, and cost-effective, making them common in laptops. The video discusses the advantages of LCDs, such as their low power consumption and affordability, which contribute to the overall utility and portability of laptops.

💡Backlight

A backlight is a source of light that illuminates the screen of an LCD display from behind. The video explains that the backlight, which can be fluorescent or LED, is necessary for the display to show colors and images. The type of backlight can affect the quality of the display, with LED backlights being thinner and more energy-efficient than traditional fluorescent ones.

💡Twisted Nematic LCD (TN LCD)

TN LCD refers to a type of LCD panel that uses a twisted nematic liquid crystal structure. The video mentions that TN LCDs offer fast response times, making them suitable for gaming or applications with fast-moving graphics. However, they often suffer from poor viewing angles, which can lead to color inversion when viewed from the side.

💡In Plane Switching (IPS)

IPS is a technology used in LCD panels to improve the viewing angles and color reproduction. The video describes IPS LCDs as providing better color representation, which is beneficial for graphic design and desktop publishing. While they offer superior image quality, IPS displays are slightly more expensive than TN displays.

💡Vertical Alignment (VA)

VA is another LCD panel technology that offers a balance between the fast response times of TN and the color accuracy of IPS. The video notes that VA displays have good color representation but slower response times compared to TN LCDs. This technology is for users who want a middle ground between the two other technologies.

💡Organic Light Emitting Diode (OLED)

OLED is a display technology that uses organic materials to emit light when an electric current is applied. Unlike LCDs, OLEDs do not require a backlight, making them thinner and more flexible. The video highlights OLEDs' use in modern devices like tablets and smartphones due to their high color accuracy and energy efficiency.

💡Wireless Antennas

The video discusses how the display of a laptop can also serve as a location for wireless antennas, which are essential for 802.11, Bluetooth, and other wireless networking technologies. This is an important aspect of laptop design, as it allows for the integration of wireless capabilities within the laptop's structure.

💡Webcam Integration

The video mentions the integration of webcams into laptop displays, which is a common feature in modern laptops. This integration allows for video capture and facilitates video conferencing and online meetings, enhancing the laptop's functionality for communication purposes.

💡Cold Cathode Fluorescent Lamp (CCFL)

CCFL is a type of backlighting used in older LCD displays, which requires more power than LED backlights. The video explains that CCFL backlights use inverters to convert DC power from the laptop to AC power needed for the backlight. Understanding CCFL is important for repairing or replacing displays in older laptops.

💡Digitizer

A digitizer is a component in a display that converts analog input, such as from a stylus or touch, into digital signals that a computer can process. The video describes how digitizers enable high-resolution input on devices like tablets and hybrid laptops, allowing for direct interaction with the display.

💡Touch Screen Digitizer

A touch screen digitizer is a specific type of digitizer that allows for input from a user's finger touch, converting it into digital data. The video explains that this technology is common in laptops and tablets, providing a user-friendly way to interact with the device, in addition to traditional input methods like keyboards.

Highlights

LCD displays in laptops are lightweight and use minimal power.

LCDs are cost-effective, contributing to lower laptop prices.

Achieving true black on LCD displays can be challenging due to backlighting.

LCD backlights can be fluorescent, LED, or other types, affecting display quality and repairability.

TN LCDs offer fast response times, ideal for gaming and fast-moving graphics.

TN LCDs suffer from poor viewing angles, causing color inversion when viewed from the side.

IPS LCDs provide excellent color representation, beneficial for graphic design and desktop publishing.

VA displays are a middle ground between TN and IPS, with good color but slower response times.

OLED displays are thin and light, as they do not require backlights or glass protection.

OLED technology allows for self-emission of light, enhancing portability in devices like tablets and smartphones.

Laptop displays are strategically used for wireless antenna placement due to their high position.

Replacing a laptop display requires careful reconnection of video and wireless antenna wires.

Webcams are often integrated into laptop displays, facilitating video calls and meetings.

Older laptops may use CCFL backlights, which require more power and have larger inverters compared to LEDs.

LED backlights are thinner and more energy-efficient, often referred to as 'LED displays'.

Hybrid devices with digitizers allow for high-resolution stylus input, converting analog to digital signals.

Touch screen digitizers convert finger input into digital form for system use.

Transcripts

Many of the laptops we use today have an LCD display.

This is a liquid crystal display where

there are a series of liquid crystals associated with color

filters, and there is a backlight or light source

behind all of that shines through to give us

the image that's on our screen.

From a laptop perspective, the advantages of an LCD display

is that they are lightweight and use very little power,

and they're relatively inexpensive to make, keeping

the cost of the laptop down.

There are some disadvantages with LCD displays.

One is that this light source in the back

has to shine through to provide the color, which

means getting a true black can be quite difficult on an LCD

display.

We might also have different kinds

of backlights on our displays.

The light source may be fluorescent, it may be LED,

or may be some other type of light.

If this backlight was to fail, you

could see that it's part of the display itself,

making it relatively difficult to be

able to repair or replace.

There are three different technologies

of liquid crystal displays that you need to be aware of.

One is the TN LCD, this is the Twisted Nematic LCD,

which gives us very good response times.

If you're a gamer or you're using some application that

has fast moving graphics, this may

be the display type for you.

Unfortunately, these displays often

have very bad viewing angles, which

means once you get off to the side of the display,

you'll notice there's an inversion of the color.

If you want the best possible view of a TN LCD,

you need to be looking directly at the display.

If you're looking for the best possible color

representation on an LCD display,

you'll want to use an IPS LCD.

The IPS stands for In Plane Switching.

This gives you very good color representation,

which is great for using graphics or doing some type

of desktop publishing.

But these are slightly more expensive than a TN.

So that extra color representation

comes at a bit of a cost.

If you like something that's in the middle between TN and IPS,

you may want a vertical alignment LCD or a VA display.

This has good color representation,

but you'll find the response times are a bit slower

than a twisted nomadic LCD.

If you have a newer device, you may be using an OLED display.

The OLED stands for Organic Light Emitting Diode.

And it doesn't have a backlight.

Instead, this organic material emits light

when you provide it with a current.

Because there's no backlight and no liquid crystals,

these are very thin displays.

And there's no glass that you would

need on the front of the display to protect it.

The real key is that organic material

that's able to create its own light when you provide it

with power.

And that's what allows these displays

to be very light and very thin.

You'll find them on tablets, phones, and smart devices,

not only because they provide such great color

representation, but because they're

so light and so easy to carry.

One aspect of our laptop displays

that we don't often think about is how they're

used on wireless networks.

When you open the laptop, your display

is the highest component in that system.

So it's a perfect place to run your wireless antennas.

If you're using 802.11, Bluetooth,

or some other type of wireless networking,

then you probably have an antenna

that runs to the top of your laptop display.

This creates some challenges when

you are replacing the display, because you not only

have to remember to connect all of your video components,

you have to remember to connect all of these antenna wires

as well.

Here's a picture of a display.

This one does look a bit damaged.

You can see the primary connection

that we use for the video signal.

But coming out of the other side of the display

is a white and a black wire that's used for 802.11.

You need to take care when replacing this display

that you're following the same path that the previous wires

took, so that you could connect all of those wireless

antennas to the appropriate components on the system board.

This is what it looks like when everything is in place.

You can see some antenna wires coming out of the system board.

They're wrapping around the system.

And these appear to wrap all the way

into the top of this particular laptop.

If we look closely, we can see wires

that are used for the 802.11 network.

There are some additional wires also

at the top of this display.

These are the wires that are used

to bring the signal from the audio and video associated

with the webcam.

Many laptops these days have webcams

integrated into the laptop itself.

That's that small little hole at the top

for the camera and a tiny little right next to it

for the microphone.

This can obviously be used for video capture,

but it's also used for meetings and video conference calls.

This makes it easy when you need to be on a Zoom call.

You can simply open your laptop display,

and the camera built into the display

will be able to show you on the call.

Here's a better shot from this laptop, which clearly shows

that this is the webcam that's integrated

into the laptop display.

And you can see there are holes also

for the microphone in the display as well.

We mentioned earlier that a liquid crystal display

needs some type of light behind the system

to shine through so that we're able to see

the images on the screen.

If you're working with an older laptop,

this might be a fluorescent type of light, specifically

a CCFL or Cold Cathode Fluorescent Lamp.

These require a bit more power than the LED lights

that we tend to use today.

And you'll find the LED back lights are also

a bit thinner, taking up a lot less space

on your laptop computer.

If you're working with an older laptop

or you need to replace the display on an older laptop,

you may find that the backlight that it's using

is a CCFL backlight.

Newer LCD displays might use LED lights instead

of using a fluorescent lamp.

These LED lights may be around the edge of the display

or they might be in a matrix, such as the one that's

seen here.

These have become so common that instead of people referring

to this as an LCD, they often refer to it as an LED display.

What they really mean, of course, is an LED backlit LCD.

If you were to pull the front off

of a display that has LED backlights,

you might see the matrix behind it looking like this.

These are strips of LED lights.

And you can see each one of these LED lights

is in a very large matrix behind the display.

The display is smart enough to recognize

what parts of the display should be lighter or darker

and will adjust the lighting depending on what

you're viewing on the screen.

If you're working on one of these older laptops

with CCFL or these fluorescent backlights,

you may also find some additional components

behind the screen.

These are inverters.

We use these inverters because the CCFL backlight requires

AC power, but your laptop is using DC power.

The inverters are responsible for taking that DC power,

converting it to AC, so that we can power

those fluorescent back lights.

One way to tell if your backlight has failed

is to shine a flashlight directly at the screen.

If you're able to make out some of the information

on the screen, then it's very possible

that the problem is not with the display,

but with the backlight behind the display.

If this is a CCFL backlight, you may just

need to replace the inverters, and you'd

be able to restore the backlight.

On some systems you may have to replace the entire display.

You'll have to check with the documentation for your laptop

to see what applies for your particular model.

If you're using a hybrid device, like this one that

has a keyboard and a tablet type display,

you may be able to use a very high resolution

input with this stylus.

That stylus allows you to directly draw on the screen.

And whatever you're pushing on the screen

is converted into digital signals in the display.

We're able to provide that conversion

because inside of this display is a digitizer that converts

that analog input onto the display into digital signals

that the computer can use.

The digitizer in your device may only allow for stylus input,

or it might also provide input using a touch screen.

A touch screen digitizer takes input from our finger,

converts it into a digital form to be used by that system.

It's a very common way to get information

into a laptop or a tablet.

And we can often use a keyboard, a stylus, or key presses

all on the same system to perform this input function.