How do LCD Projectors work? – 2022 Guide

Projectors have been developing for a long time and they have come far from what they used to be. But why is a projector important?

Sometimes during presentation tablet may make some issues use of its screen size, so there is a need for the projector to generate images from a tablet, laptop, or Blu-ray player and reproduce them by projection onto a screen, wall, or any other surface. In most cases, the surface on which the image is projected is large, flat, and lightly colored (ideally white). It is important for purposes where you need to show a presentation on a large screen as in tablets the max screen size can be near about 11 inches. Projectors can produce both, still (slides) and moving images (videos).

lcd projector

Projectors have been subjected to technological advancements for a while now. 

In this article, I will take you through an in-depth analysis of what an LCD Projector is, how it works, and its various types and features of the same. Also mention how and why you should pair up your projector with a Graphics Tablet and make the most of both technologies. 

What Does an LCD Projector Mean?

An LCD projector is a type of projector based on Liquid Crystal Displays which can display images, data, or video. They work on transmissive technology. A Liquid Crystal Display projector is an output device used to magnify the presentations prepared on a computer/laptop. It accepts data/information from the CPU where it is stored internally and projects it on an external screen.

With the help of a small LCD panel, the data is fed into the Projector and then passes through a convex lens. The presentations are therefore received on the screen in a magnified form. LCD projectors are more popular and preferred than most alternatives since they are cheaper to produce and have excellent color reproduction on the screen. They are commonly used in business meetings, presentations, and seminars for projection.

The digital projectors broadly come in two types: For more details, you can read this post

  1. LCD (liquid crystal display) Projector 
  2. DLP (digital light processing) Projector 

lcd vs dlp

Characteristics of LCD Projector:-

1- Constant Colour

LCD projectors are distinct for putting every color on the screen at the same time. This is different from that of one-chip DLP projectors that switch red, green, and blue multiple times per second. This causes a distracting optical illusion which we call the “rainbow effect”. This happens in a form that is particularly asserted on images that have crisp edges between light and dark regions, for example, presentation slides. It is this characteristic that makes LCD projection well-suited for business presentations for mid-sized or large groups where it is plausible that at the minimum one viewer would be unsettled by a DLP image.

characterstic of projector

2-Sharpness

When compared to a DLF projector, LCD has an advantage concerning its uncomplicated light path. Due to this, it can produce sharper images. By stating that LCD projectors produce sharp images, I, by no means say that the other projectors available in the market are blurry in their image quality. I rather say it as when an LCD and DLP image is projected next to one another, the LCD images are experienced to be crisper than DLP, especially with a comparison between the text and graphical content that has been one of the most used causes by business presenters lately.

3- Brightness

LCD projectors by default produce brighter and good saturation images. This is made possible as the lamp’s light inside an LCD projector directly passes through the image elements to the lens. This way allows only a negligible bit of light to get lost along the way. This means that most of it reaches the screen and helps in producing a good quality clear image on the screen.

4- Cost

Over time, LCD’s cost-benefit has gradually decreased in comparison to DLP projectors. However, LCD projectors remain on the slightly less expensive side. 

 

How do LCD projectors work?

An LCD projector works with the following parts: 

  • An optical light engine that incorporates three small LCD (Liquid Crystal Display) panels, one each for Red, Green, and Blue paired with a
  • Source of light (lamp, Discrete RGB Laser, LED, Laser Phosphor)
  • various filters, 
  • mirrors and 
  • a prism to create the image.

projetor work

Parts Of An LCD Projector

The inner workings of an LCD projector are made up of various components that include

a light source, regular and dichroic mirrors, a dichroic combiner cube/prism, 3 LCD panels (RGB), and a lens.

  • Light Source

Typically the light source of an LCD projector can either be bulb-based or laser-based.

With a bulb-based projector, the light that comes from the lamp is white. White light, as known, is made up of all different colors. To use that white light to create the colorful image that one sees on the screen, the light needs to be broken up into its constituent colors red, green, and blue.

  • Laser LCD Projectors

With respect to a laser projector, the light source is typically a single blue laser. The reason for a blue laser being used is because, on the color spectrum, blue is closest to white, the cheapest, and can get the brightest based on current technology available.

These laser projectors feature a phosphor wheel. This phosphor wheel consists of a chemical that radiates yellow or white light when blue photons from a blue light source hit the surface. This can then be used to create the other colors that are seen in the final image.

  • Mirrors

The mirrors used in an LCD projector are of two types:

The first can be termed as basic mirrors. These redirect the light which enables it to shine where it is needed in order to create the image. Typically, you will be able to spot 3 regular mirrors in your LCD projector.

The second type is the dichroic mirrors. These mirrors reflect only particular colored wavelengths of light as they let the other wavelengths pass through. Dichroic mirrors split the white light into each of its constituent colors which are red, green, and blue. Typically, you will be able to spot two dichroic mirrors in one LCD projector.

  • LCD Panels/LCD Chips

Basically, an LCD panel is just a glass panel with liquid crystals installed into it. These liquid crystals are triggered by an electrical charge carried through to each of the panel’s pixels via the wire grid located throughout the LCD panel, around every pixel. Each LCD panel consists of individual cells or pixels. Each pixel is therefore controlled by its respective transistors.

A pixel’s transistor applies electrical current to the liquid crystal within its cell.

The resolution of the display is determined or dependent upon the number of such pixels that the LCD panel contains. The number of pixels, horizontally and vertically, in each direction is subject to change based on the aspect ratio required to be displayed on the screen. It is also called a 3LCD chipset because an LCD projector has three panels for each of the primary colors, red, green, and blue.

  • Dichroic Combiner Cube/ Dichroic Prism

The dichroic prism divides a ray of light into red, green, and blue color constituents to form three pictures that utilize these corresponding primary colors from the LCD panels. The three primary colors are put together again by reflecting the red and blue light and passing through the green light. 

The prism in an LCD projector is built by combining four triangular poles to create one rectangular prism.

  • Lens

An LCD projector uses two kinds of lens, these are: 

  • A polarizing lens and
  • A projection lens.

I’d define a polarizing lens by its feature of focusing the beam from the light source and it polarizes the light making the beam appear brighter to the eyes. A projection lens on the other hand is the part of a projector that magnifies the image that comes out of the combining prism and then projects it onto the projection screen.

 

Let’s understand what enables an LCD Projector to create the image on the screen

The first step in this process of projecting an image in any LCD projector is the light source. I can say that this source can either be a bulb, LED, or laser-powered light. The light beam travels through an initial lens that focuses the beam to its expected direction and polarizes the light latitudinal, which increases its brightness by 1.5x. 

When dealing with a laser projector, the light is required to be altered from its initial blue state to white or yellow light. This is done so that it can be split into separate red, green and blue beams of light. It is made possible with the use of the phosphor wheel.

projector on screen

The next step includes the blue light passing through the clear segments of the phosphor wheel and following on. Then when the blue laser hits the yellow segment of the phosphor wheel, it excites the phosphor which makes the beam turn yellow. This can later be split into red and green. After the white or yellow light has been obtained, the process between all the light sources is totally the same. However, the order in which the light is split may be different from one setup to the other.

Third step involves the light hitting the first dichroic mirror. This allows the blue and green parts of the white light (which form cyan) to pass through it while reflecting the red part of the light. Furthermore, the cyan light continues passing straight through the next dichroic mirror as blue, while the green light is separated and reflected towards the green panel. In the meantime, the red beam of light reflects off a mirror towards the red LCD panel.

Then the blue beam of light reflects off two mirrors so that it properly hits the blue LCD panel at the exact position. The beams then hit the surface of the LCD chip and create a red, green, and blue image on each of the respective panels. Since the colored beams travel at the speed of light, they all hit their respective colored LCD panel at essentially the same time frames.

Combining The 3 Images: 

Once passing through the LCD chips has happened, the 3 colors of light hit the dichroic combiner cube. It is at this point that the image is combined into one multicolored image which is further beamed through the lens and projected onto the screen and we can see the final projection.

 

Graphics Tablet with your LCD Projector – A splendid combination!

A graphics tablet, often known as a drawing tablet or a pen tablet, is a natural input device that transforms data from a handheld stylus. The stylus is used by the user by pressing its tip against the tablet’s surface just like a pen, pencil, or paintbrush. Additionally, the tool can take the place of a computer mouse.

The cool features on tablets, which can be used in a variety of ways, make them fantastic. One method is to pair them with your projector to create an engaging presentation.

Why should a tablet and projector be used together?

Your projector will become an interactive gadget when connected to a tablet, making it the ideal platform for lectures and presentations. Additionally, it makes it simpler for students to participate in class. There is one tablet that comes with the projector itself, Lenovo Yoga Tab 3 which is can do both.

The following are some advantages of using a tablet with your projector:

  • simple to operate and use
  • a reasonable pricing range
  • can raise the interest level of any presentation.

tablet with projector

How do the tablet and projector interact?

The projector is the device that shows images on a screen, while the tablet is the device that can project an image onto a screen. We refer to the combination of these two devices as “a multimedia system.”

Tablet manages the computer’s mouse, keyboard, and any additional features like brightness or volume. This enables you to manage everything with your hands rather than your feet.

This can be ideal for you if you want something that is more portable than a laptop and easier to transport than a desk arrangement.

 

What tablets would be ideal to use with your LCD Projector?

A Projector is a tool that lets you display images. The iPad and Samsung Galaxy Tablets are counted amongst the finest tablets for projector use if you wish to utilize your projector with a tablet.

However, I would point out the disadvantages of utilizing an iPad being poor image quality or blurry photographs and having to purchase an additional adapter if you already own one from Apple. On the other hand, high-quality tablets that function well with projectors without additional adapters are available from manufacturers like Dell, Acer, and Lenovo.

Thus I would suggest you try looking for a tablet that has at least an 8-inch screen, runs on the Android operating system, and has Bluetooth capability.

The following are your options for connecting your android tablet to Projector through hard-wired connectivity:

  • USB-C port
  • Micro-USB port
  • Built-in HDMI port
  • VGA port
  • Audio output port

 

Conclusion 

I can list several advantages of using an LCD projector. One is, that higher lumen output can be delivered by an LCD projector at a lower cost when compared to a digital light processing (DLP) projector. It also provides higher brightness with lower energy consumption.

However, on the good side, unlike DLP projectors, LCD projectors do not suffer from rainbow effects and dithering. Another important feature of projectors is their image sharpness and greater zoom magnification.

That also provides for certain disadvantages associated with LCD projectors. They are comparatively bulkier than other projectors. This results in making it less portable. The panels however have a limited lifetime, they lack high contrast and might suffer from black and dead pixels. Maintenance is usually higher in the case of LCD projectors when compared with other projectors.

In cases of using an LCD projector frequently over a long period, image degradation is possible. Moreover, they also heat up more quickly than DLP projectors. So that’s all about LCD projectors and how they function, choose wisely!

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