Laptop Displays – CompTIA A+ 220-901 – 3.2

| December 18, 2015 | 0 Comments

Our laptop display technologies incorporate visual output, cameras, microphones, antennas, and more. In this video, you’ll learn about some of these portable display technologies and how we use our laptop displays for much more than just viewing our computer’s output.

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Most of our laptops these days use liquid crystal displays. These LCDs work by shining a light that’s on the backside of this display. And it shines through a set of liquid crystals and eventually color filters that make up the display that we see. Some of the advantages of LCD are that they are very lightweight, they use very little power, and they’re relatively inexpensive to make. So it’s perfect for a mobile device.

One of the challenges we have with LCDs is that it can be difficult to properly represent some colors, especially black. Because we’re shining a light through this display. It’s difficult to get a very, very dark pixel to show as a true black color on an LCD. These also do require that a light is behind this display. This light can be fluorescent or LED. But if we have a problem with that backlight, then we’re not going to be able to see anything on this display.

You’ll generally find two different kinds of LCD. One is the TN, or Twisted Nematic, LCD. Has very fast response times. You’ll often see this display being used by gamers. It also has a very low power draw. So it’s very good for portable devices. Unfortunately, it has a poor viewing angle. So it’s really seen best if you are looking at the display directly in front. If you’re off to the side, you may see an inverting or shifting of the color.

Another type of LCD is the IPS, or In Plane Switching, LCD. This has excellent color representation. And it doesn’t discolor or tail when you touch the device, which is great for mobile devices. Unfortunately, it’s a little more expensive to produce than the Twisted Nematic LCD.

You’ll tend to see both TN and IPS displays being used on a laptop. Just depends on exactly what model you’re getting. You tend to see the IPS and the more expensive In Plane Switching LCD on the higher end laptop computers.

With LCD technology, you must have a backlight to be able to see anything on the screen. Our older laptops used CCFL as the back light. This is a Cold Cathode Fluorescent Lamp. It used quite a bit of voltage– much more than the ones that we use these days. And so it used a lot more power on our laptop computers. They were also relatively thick. So we don’t really use this commonly on our laptop computers these days.

So today we use LED backlit LCD displays. You may sometimes see this written as an LED display. What that really means is that there is an LED backlight on this LCD display. This type of display usually puts LEDs either around the edge of the screen, or there might be an array of LEDs that will brighten or darken even in different areas of the screen, depending on what you’re looking at on your display. Most of the new laptops today are going to be LED backlit.

A very interesting mobile display technology is OLED. It stands for Organic Light Emitting Diode. This is a display type that emits light when you provide power to particular organic materials within the display itself. OLED displays are very light. They’re very flexible. It doesn’t require any glass on the display. So you can really fit it to a lot of different kinds of mobile technologies.

OLED also doesn’t require a backlight. So you can fit it into very small types of environments, especially on mobile devices. The organic compound itself is what’s lighting up inside the display. Unfortunately, this organic material degrades over time. Sometimes it can leave images on the screen. It’s also more costly than an LCD. So we don’t tend to see OLED being used today for our laptop computers.

On a laptop display, there are a number of different wireless antennas. For your 802.11 networks, you have a Wi-Fi main and an auxiliary antenna wire. And you also need an antenna wire for Bluetooth. These antenna wires are an important component of your LCD display, because the display is the highest point on your laptop. So you’ll find that the antenna wires are wrapping around the outside of your LCD display.

Here’s a view of these antenna wires. The keyboard on this laptop has been removed and has been placed right here. You can see underneath the keyboard is an 802.11 wireless adapter. And connected to that wireless adapter is a main and an auxiliary antenna wire. And you can see that these wires wrap around that keyboard underneath until it reaches the display. At that point, the wires go directly into the display. And they wrap around the outside to be able to get as much signal as possible.

Many laptops will include a webcam on the laptop itself so that you’re able to record video and audio and even broadcast that live across the network. If you do have a webcam on your laptop, there are probably specialized drivers for the webcam hardware. Even if you don’t have a webcam, there’s probably a microphone built into your laptop. You can see in this particular laptop there’s not only a webcam, but we can capture audio from the left and the right microphone that’s built into the display itself.

An LCD will need a backlight. And some of our older laptops are going to have fluorescent lamps inside of those computers. If you do have a fluorescent lamp, then you’re going to need an inverter that is used to be able to convert from the DC that’s inside of your laptop to the higher voltage AC that’s used by these fluorescent lamps. If your inverter fails or you have a problem what that inverter, then the lights are not going to work on the backlight.

You may need to look closely at the screen to see if you can see anything at all. You may be able to make out some of the images on the screen even if a backlight isn’t present. If you are able to see images on the screen and you’re simply not receiving any light through the screen, then you may have to replace the LCD inverter or the entire display itself.

Many of our newer laptops allow us to draw right on the display itself using a digitizer. This is where we can use something that looks very similar to a pen to write directly on the screen itself. It’s very common on some of our newer laptops or even these hybrid devices that allow you to connect and disconnect a keyboard so that you can convert between a traditional laptop view or use it as a tablet.

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Category: CompTIA A+ 220-901