What Is LED Monitor?

An LED Monitor is flat screen computer monitor that uses light emitting diodes as backlight. They are in typically less expensive than LCDs, more reliable, operate at lower temperatures and consume less power.

LED Monitor Definition

Technically speaking, every monitor is output device that presents informations from computer on a screen. Difference between them is in most cases type of backlight used to illuminate thin film of liquid crystals in front of them.

LED vs LCD Monitor

Main difference between LED and LCD computer monitor is backlight. LED monitors use light emitting diodes as backlight while LCD monitors use cold cathode fluorescent lamps. Because of that, LEDs use less power.


Difference Between LED Display, Panel and Monitor


An LED display is just the same as LED Panel, it is flat panel display that uses light emitting diodes as pixels. In other words, light emitting diodes are individually placed in an array. Since they are very bright, LED displays are often used outdoors as billboards and store signs. In last few years they are commonly used in public transport vehicles or as destination signs.

An LED Monitor on the other hand is computer monitor with liquid crystals, just like LCD, but instead of cold cathode fluorescent lamps, LEDs use light emitting diodes as backlight source. There are different types of LED displays and I will explain them but let's see first how LED monitors work.


How LED Monitors Work?


An LED monitor is actually an LCD monitor. Only difference is backlight used for illumination. While LCD use cold cathode fluorescent lamps (CCFL), LED monitors use light emitting diodes (LED) as source of backlight. They are more energy efficient and thinner than monitors with CCFL. Although marketing companies made a lot of noise when LEDs were introduced, compared to LCDs they don’t provide much quality improvement.

LED monitors are composed from two parts:
- Liquid crystal display
- Light source at the back of the screen

Light diffuser is placed between light source and liquid crystal display in order to make the source of light more uniform across the whole screen.

Only difference between types of LED monitors is in light source that is placed at the back of the screen. Therefore, we have 3 different types of LED monitors:
- Direct Lit
- Edge Lit
- Full Array

Direct Lit LED Monitors

Direct lit LED monitors belong to lower end of LEDs because of their construction. They are most similar to full array LED by design. But, considering the number of led diodes (there is just few of them) they can not be controlled separately. Direct LED monitors are a bit thicker than Edge Lit LEDs.

By design, they resemble to LCD monitors. Primarily we have them because of their price. This type of monitor is often cheaper than edge lit models. In most cases they are least expensive models on the market with leed diodes. Main advantage over classic LCD models is their energy efficiency.

Direct Lit LED Backlight

Edge Lit LED monitors

They are most common LED monitors that are produced today. Diodes are placed at the sides of the screen. Depending on a manufacturer and model, led diodes may be placed all around the screen, only on one sides or only at the bottom of the screen. Because of this, monitors are really thin.

Downsides with this design is the fact that some parts of the screen are brighter than the other parts. This known problem is called clouding or flashlight. Most often you may notice this when watching a dark scene in darkened room.

Edge Lit LED Backlight

Full Array LED Monitors

These monitors are considered to be the best monitors with light emitting diodes because of their design. Main drawback is the fact that companies are not producing this type of monitors very often. Most series are limited and number of them is small on the market. In most cases they are a more expensive than Edge Lit LEDs.

By design as their name suggest, led diodes are placed evenly behind the entire surface area of the screen. Thanks to this, they produce uniform backlight. Because of that fact, local dimming is more effective so just part of the area can be illuminated while other parts may be black.

Full Array LED Backlight

Different Monitor Panel Types

You are familiar that monitors come in various sizes and resolutions. Some of them have glossy screen while others are with matte screen surface. Also, monitors can with features like 3D capabilities or 120Hz refresh rate. While we all look at the specifications and say: “WoooW!” but we forget one fundamental difference between all of them - type of the panel!

We may divide all monitors in three groups by the type of panel that they have:
- TN (Twisted Nematic) Panels
- VA (Vertical Alignment) Panels
- IPS (In-Plane Switching), PLS (Plane to Line Switching) and AHVA (Advanced Hyper-Viewing Angle) Panels

TN Panels

For decades now, TN Twisted Nematic) panels are with us on the market. Manufacturing companies point their specifications rather than saying that it is TN panel. If manufacturer don’t explicitly state what kind of panel it is - count it as TN panel.

In general, they are cheap to produce and have high responsiveness. Pixels change their state pretty quickly so image appear to be smoother. In most cases gamers tend to purchase monitors with TN panels because of those characteristics.

Some TN displays have double refresh rate (120Hz instead of 60Hz). Most recent models are promoted with 144Hz refresh rate. They provide fluid 2D experience rather than 3D.

During past years, manufacturing companies have improved image quality of TN panels, but to be honest, image quality is not their stronger side. Although, good quality TN display can provide vibrant and crisp image with good contrast (usually 1000:1 - dynamic contrast disabled).

Main drawback is restricted viewing angle, in most cases quoted as 170 degree horizontal and 160 vertical. In plain words, when you try to look at them from the sides you will notice change of color.

Because of their restricted viewing angle, they are produced in sizes up to 28 inches. Event if there are bigger models, purchasing one of those would be really poor choice as even if you sit dead in front of them you would see color changing on the sides and corners.

VA Panels

Main problem for any LCD monitor is reproducing black color. When LCD tries to display black color, filter needs to let as little light as possible (if any) from the backlight.

In overall, all of them do this job reasonably well but filter is not perfect and black color is never deep as it should be. Main strength of VA (Vertical Alignment) panels is their ability to block backlight when displaying black color.Because of this they have better contrast ratio - from 2000:1 to 5000:1 (dynamic contrast disabled).

They are most often picked up by the people who enjoy watching movies in darkened room as they have less issues with clouding or light bleed.

Another advantage over TN displays is viewing angle and color reproduction. They are able to reproduce color shades with great precision but still, they are behind IPS or PLS displays.

Their main drawback is low level of pixel response when they are transitioning from one state to another. This could be noticed in fast paced video games or during fast moving scenes as some blurring may occur.

Of course, in recent years we have models with VA panels that compensate those drawbacks. Because of that you may find all kinds of different abbreviations like: MVA, AMVA, AMVA+ and so on.

IPS, PLS and AHVA Panels

When we speak of end results, there are three types of panels that are very similar. Main difference behind those IPS displays is manufacturer. As a company, LG produces IPS panels, Samsung produces PLS panels and AUO produce AHVA panels.

Best selling point of those screens is their superior color accuracy, great viewing angles and consistency compared to other panels. Some high end IPS and PLS models have expanded color gamuts which increases shade range and have even higher color depth.

Because of this, those panels are must when working with colors (graphic designers and general desktop work). Very often, large IPS models feature higher resolution than TN or VA models.

Now, people often think that IPS monitors are very expensive. Well, to be honest they can be but they were expensive once they were introduced to the market almost decade ago.

Nowadays they are really affordable. More and more manufacturers tend to produce them so we can find models from LG, DELL, AOC and ASUS on the market.

Traditionally, main drawback of IPS panels was responce time so gamers were moving away from them. In recent years, latest models were produced with improved response time so they are in range of 60Hz TN panel monitors.

At 120Hz refresh rate responsiveness is not quite up to the task. Other drawback that was improved over the past few years was color contrast of around 1000:1 (without dynamic contrast).


Matte or Glossy Screens

More often than not, manufacturing companies misrepresent their product and they are poorly understood by consumers. One monitor attribute is discussed by users pretty often - screen surface. Unlike CRT monitors from the past, modern monitors are not restricted by reflective glass surface.

Glossy and Matte display screen compared side by side

Source of this side by side comparison of Matte and Glossy display is laptopscreen.com


Matte Screens

Matte screen have outer polarizing layer that is coarsened with mechanical and chemical processing. Very often manufacturers use multilayer sputtering or several passes of deep coating followed by surface treatment with chemicals. I will not get into production methods in this article as we are more interested in end results.

Matte screen finish is created to diffuse ambient light instead of reflecting it back to the viewer. Outer surface is something like a mirror. Since glare is reduced we often call this as anti-glare. This optical property has its drawback since this surface works both ways - light emitted from the monitor is also affected.

Advantages:

- Reduced glare improves visibility

- Potentially less eyestrain

- Dust and dirt less visible

Disadvantages:

- Reduced contrast and color vibrancy

- Reduction of sharpness

- More difficult to clean


Glossy Screens

Glossy screen has smooth outer polarising layer. Rather than defusing, their surface tend to reflect back ambient light causing unwanted glare and reflection. On a positive side, light emitted from the monitor is not interfered by finishing process so colors appear to be richer and more vibrant.

Latest computer monitors are treated with anti reflective chemical coating that absorbs ambient light. Therefore, you may see that manufacturers call their models: Dell TrueBright, HP BrightView, Sony Xbrite, ASUS ColorShine, etc. By knowing this, you will understand what method is used to reduce glaring.

No matter what technology is behind creating anti reflecting coating, glossy screens tend to reflect ambient light. In order to compensate this, user's push brightness of their monitor to the maximum. Even though reflection of ambient light is reduced, anti reflecting coating can not eliminate this effect.

Advantages:

- Reduced reflection in certain conditions

- Easier cleaning

- Better aesthetic appeal

- Cleaner image

Disadvantages:

- Direct light causes reflection

- Strong ambient light causes reflection

- Potentially increased eyestrain

- Dust and dirt more visible


LED Monitor Features and Connections (Ports)

When you take a look at names of LED monitors, from the name you will recognize panel type and what kind of coating was used in production. We have covered that in previous sections. Now, when shopping for LED monitor you will find yourself looking at all kind of specifications, additional features and connections. Now I will list what you need to understand, so pay close attention.

I will start with connections. LED monitors are typically produced with few different connections for connection with your PC or console. Most common connections or ports are:

- DVI

- D-Sub

- HDMI

- USB

- Audio In/Out

- Speaker

Important Note: for connecting HDMI devices pay attenting on HDMI rating of your monitor. For example, HDMI 1.2 supports up to 1080p resolution, HDMI 1.3 support up to 1600p. For 4K resolution you need monitor with HDMI 2.0 port. Display port 1.2 and newer supports 4K resolution.

When searching for LED monitor, if you want to make sure that you have bought right one for your money - you need to pay attention to following features and specifications. Once you know what you need, you will know exactly what to look. Most common features or specifications:

- Panel Size - panel size is measured from corner to corner (diagonally). We have 19, 21, 25, 27 inch monitors, etc.

- Aspect Ratio - ratio of the image in relation to the height vs width of the monitor. Most common aspects are 4:3 and 16:9

- Response Time - time needed for pixel to change color from white to black and white again. Effectively, time needed for pixel to change color from one to another.

- Contrast Ration - difference between brightest white and darkest black. Look for static contrast at least 1000:1.

Brightness - brightest white that can be displayed measured in cd/m2.

- Viewing Angles - typically displayed as 170/160 (170 degree horizontal, 160 degree vertical viewing). IPS have best viewing angle offering 178/178 degrees.

- Refresh Rate - typically between 60-75 Hz, modern monitors with 120Hz. Even if your panel is more than 60Hz, if you connect it to DVI it will be capped at 60Hz.

- Color Depth - how many colors it can produce, most common is 16.2 million colors (8-bit), 1.07 billion (10-bit) monitors.

- Pixel Pitch - distance between pixels. Tighter pixels produce sharper image.


Final Words

Considering that there is so much to tell about OLED and Ultra HD monitors, I will let that for another article. Please, make sure to check other articles on my site as well as I will do my best to explain you want to know in plain language. If you think that something is not true in my text, please send me an email and I will check my sources once more.

I`m really interested in knowing what you have t say about LED monitors. Since it is a bit complicated for me to put comments here on site feel free to send me an email. I will edit this page adding you thoughts, observations or anything you have said.