How does an LED projector work?

10 January 2021

Have you ever been to the movies and found yourself wondering exactly how the images are shown on the screen? The answer is a projector. From movie theatres to boardrooms, classrooms to your very own home, a projector is a super versatile piece of kit. But, how does it work? From the specifications to the pros and cons, we explain all.

So, how does an LED projector work?

Before we discuss exactly how an LED projector works, first we must understand projectors in general. A projector is simply a technological device that is used to project an image from a computer, TV or gaming system onto a screen. It works by shining and filtering light through a small, transparent lens, and projecting this onto a screen.

Unlike a typical lamp-based projector, which uses coloured filters, or colour wheels to generate colour, in an LED projector, a combination of red, green and blue LED bulbs are used to create a white light that is then filtered through the lens to form an image on the screen.

What about the specifications?

When it comes to purchasing the right LED projector for you, there are a number of things to bear in mind:


Measured in ANSI lumens, projector brightness is key if you want to be able to see your image clearly. This is because, the more lumens, and therefore the brighter the image, the less affected by ambient light your image will be. If a projector has a low number of lumens, you’d only be able to see the image in a dark room as any other light sources would make it very hard to see.

Typically, if you’re looking for a great picture for outdoor viewing, a good brightness for a projector is around 2000-3000 lumens, but this does depend on a number of other factors such as the brightness of the sun and the quality of your screen.

Throw Ratio:

In order to create the right image size, you’ll need to properly calculate your throw distance to figure out the model you need, along with where you’re going to put the projector itself. Throw ratio simply refers to the distance between a projector and the screen and is worked out using the following formula:

Distance (D) divided by image size (S) equals the Throw Ratio (T)

Depending on your distance, there are a few different types of projector you can choose from:

  • Standard Throw: ideal providing larger images, standard throw projectors are usually installed in the center of the ceiling and are perfect for big rooms
  • Short Throw (ST): with a throw range of 3 to 8 feet, short throw projectors are an extremely versatile option
  • Ultra Short Throw (UST): these projectors work from anywhere between 0 to 4 feet away, making them ideal for smaller spaces

Aspect Ratio:

Aspect ratio refers to the ratio of the width to the height of a projected image or screen. For example, a 4:3 display produces a more square image that is 4 inches from left to right, and 3 inches high, while, for a 16:9 ratio, the image will be more rectangular, and 16 inches by 9 inches.

Contrast ratio:

Contrast ratio is the difference, or contrast, between the lightest and the darkest pixel on the screen, and determines the quality of your picture. A higher contrast ratio will create a clearer image with more distinct colours.

In order to connect your projector to your games console or streaming device, you’ll need to take advantage of the various ports and connections available on the device itself, but it isn’t quite as simple as just plugging it in and switching it on.

Instead, there are several different input options available, and different devices will require a specific connection. Video cables like HDMI, DVI, or VGA, are the most commonly used connection ports on a projector, and are usually used to connect games consoles such as a Playstation 4, or a streaming device like a laptop, while other devices use various USB cable types to form a connection.
So, why should you choose an LED projector?

Now that we’ve explained exactly how an LED projector works, it’s time to find out if LED projectors are any good? Here’s what makes an LED projector great:

  • Long-lasting: when you buy an LED LG CineBeam, the bulbs themselves will last for up to an estimated 30,000 hours. This means, even if you used the projector for eight hours a day, you wouldn’t have to replace the lamp for a massive 10 years – this is great for keeping maintenance costs low, too!
  • Quieter and more compact: LED bulbs are much cooler than traditional versions, and so an LED projector is normally much smaller and quieter, as less space is needed for airflow, insulation or cooling fans, making them ideal for smaller spaces, when out and about or on your travels
  • Accurate colour: due to the combination of coloured bulbs used to create an image, LED projectors have the ability to reproduce more colours than other projectors and are immune from the rainbow effect – where the colour wheel is too slow, and so the projected image contains unwanted, or incorrect, colours.

What about laser projectors?

While LED projectors are a great choice, for the best possible experience a laser projector might be better. This is because laser projectors offer longer lasting brightness along with better colour and contrast and, when compared to LED models, require less maintenance. Similarly, the LED lights used in laser projectors are much brighter yet require no heating up, meaning less cooling is needed as inside the unit itself, and therefore the projector uses less electricity.

Whether you’re searching for a portable device for on-the-go or a more high-end projector to seamlessly integrate with your home cinema or theatre room, no matter the model you choose, we have an LED LG CineBeam for everyone.

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