How Projectors Work

It used to be that projectors were mostly found at educational institutes, places of work, and cinema halls.

However, as the technology behind projectors has improved, the price of projectors has also dropped, meaning they are becoming more and more common in people’s homes.

With a decent mini-projector available for not much over 100 dollars, and the more expensive 4K projects meaning you can get movie theatre quality in your living room, projectors are becoming a must-have.

But how do these devices actually work?

Knowing the different types of projector available, and having a basic idea of how they function, can legitimately help you maintain your projector so that it lasts longer.

So, let us take a closer look at how a projector plays your media.

Differences Between DLP, LCD, AND LED Projectors

DLP, LCD, and LED are the main types of projector you will find available.

A. DLP

A DLP (Digital Light Processing) projector has a chip inside it. This chip is made of mirrors, microscopic in size, and a spinning color wheel. From these, your image is created.

The images produced by a DLP projector are sharp, with very little in the way of lag time. These types of projectors are also very good at handling 3D images.

If there is any drawback to having a DLP projector, it is that lamp life can be quite short. Sometimes it can be as little as 2000 hours, and you’ll be lucky to find a DLP projector that can go more than 5000 hours before needing a lamp change.

B. LCD

LCD stands for Liquid Crystal Display. This projector type can be characterized by the fact it produces images without having any moving parts to do so. Because of this, LCD projectors tend to cost a bit less.

Budget LCD projectors will have a single chip, meaning lower color saturation and a noticeably darker picture. Everything tends to look a bit dull.

However, if you want to spend more money, you can get a 3-chip LCD. The aforementioned color saturation will be greatly improved, and you will get to watch your movies exactly as the directors wanted you to see them.

The drawback of an LCD is that the filter will need regular maintenance, and you will find these generally have a lower contrast ratio.

C. LED

LED stands for Light Emitting Diode.

This projector type has a significantly longer lamp life than the DLP projector we talked about earlier. On average, you will find LED projectors that can work for 20,000 hours before needing a bulb change.

Overall, the LED projector can be said to be the most cost-effective, as they require the least energy to run, and maintaining them won’t break the bank either.

These projectors have fantastic color saturation and tend to be more portable as they are smaller. You’ll also find that the heat generated by an LED projector is significantly less than other types.

If there is any negative about LED projectors, it is that their Lumen measurement (the brightness) is down compared to both the DLP and the LCD projector. Therefore, you will need a fully dark room to really enjoy the picture produced.

How Does A Dlp Projector Work?

A. SINGLE-CHIP

  1. The single-chip DLP projector works using three main components:
    • A color wheel
    • A white lamp
    • A DLP chip
  2. The color wheel is placed between the white lamp ad the DLP chip. This wheel, depending on the system being used, will be divided up into different sectors. This can be:
    • Red, green, blue, and white OR
    • Cyan, magenta, and yellow
  3. The DLP chip and the color wheel rotate in a synchronized manner. Whichever color is being displayed on the Digital Micromirror Device (DMD) comes from that color being in front of the lamp. Therefore, if red is the color given by the color wheel in front of the lamp, the DMD displays red.
  4. Viewers will see a full-color image because of the speed at which the colors are displayed in sequence. Modern DLP projectors will rotate up to ten times per frame.
  5. The depth of black color is determined by the way the light not being used is scattered. The light will either:
  • Appear grayer on screen because it has reflected and left through the DMD’s interior walls

OR

  • Be deeper black because the unused light has been directed to a separate area away from the DMD.

B. THREE CHIP

  1. A three-chip DLP doesn’t use a color wheel. Instead, it uses a prism.
  1. This prism splits the lamp’s light, producing the primary colors.
  1. These primary colors are then sent to the DMD chip, where they are combined again before being sent out through the lens.

How Does An Lcd Projector Work?

  1. The light source will produce a powerful beam of white light.
  2. The beam of white light will bounce off the LCD projector’s mirrors. Two of these mirrors are known as ‘dichroic mirrors’. These have a special coating that reflects specific wavelengths of light. The mirrors break up the white light and reflect a red beam, a green beam, and a blue beam through the projector.
  3. The colored beams of light pass through the LCD. This LCD is made up of tiny pixels. The pixels, which measure thousands, either block the light beams or allow them to pass through.
  4. The LCD screens inside the projector (3 in total) will display the same image, whether it is a still image like a photo or a moving one like a movie. This image will be in grayscale. However, when the colored light goes through these screens, they will each relay the same image but in a different color: one red, one green, and one blue.
  5. A dichroic prism recombines the separate color images to form a single image. This single image contains millions of colors.
  6. The image passes through the projector lens and onto your screen.

How Does An Led Projector Work?

This heading is actually a bit of a trick question and should really be rephrased to ‘How is an LED used in a projector?’.

In actuality, LED describes the light source being used as part of the projectors set up.

Therefore, it is possible for a DLP projector also to be an LED projector. Equally, it is possible for an LCD projector also to be an LED projector.

With that being the case, the steps shown above apply here; it’s just that the projector has an LED light source rather than some other type of bulb.

Conclusion

Though they can cost quite a bit of money, there are remarkably very few complex parts that make up a projector.

The main difference between the types of projector is that a DLP has moving parts that help create the color images you see, while an LCD projector doesn’t.

You can also find DLP projectors that come with one chip, or three chips, thus improving the image.

This article has just been a brief guide to how projectors work. If you want more in-depth science behind everything, then why not head over to YouTube, where there are loads of really helpful videos!

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