Home Theater Systems

Back when home theater projectors first hit the market, CRT Projectors were the first type introduced. Just like a television, this technology was based on the Cathode Ray Tube (CRT), on which the viewer sees the television image. The technology may have been around for a while, but it is still interesting to see how it works.

Three small CRTs (one for each primary color), coupled with a light magnifying lens, can project a color image onto a large screen in a darkened room. With the proper video processing circuitry, CRT size, and lens combination, a CRT projector can produce excellent high resolution images. To this day, the clarity and detail of a CRT projector still can hold its own; however, DLP and LCD can match it, and at a fraction of the cost.

Although this form of projector is still in use in some commercial and industrial settings, it is generally unavailable and no longer marketed for the home consumer. The market has moved in the direction of LCD and DLP projectors.

Whether you are watching your favorite sporting event, or a blu ray movie, if your home theater plan calls for the largest screen available, it may be time to look at home theater projectors. This option known as DLP looks very similar on the outside to LCD projectors, but use an entirely different technology.

What is DLP you ask? DLP stands for Digital Light Processing, a technology developed by Texas Instruments in 1987, becoming commercially available in 1996.

At the center of this technology is an optical semi-conductor called the Digital Micromirror Device (DMD). It contains a rectangular array of up to 1.3 million hinge-mounted microscopic mirrors; each of these micro mirrors measures less than one-fifth the width of a human hair, and corresponds to one pixel in a projected image.



These mirrors are capable of switching on and off thousands of times per second and are used to direct light towards or away from a dedicated pixel space (one space for each mirror). The amount of light or darkness of the pixel is determined by the length of time a pixel is turned on or off. This part of the DLP technology will only produce various shades of grey from white to black.

To add color, a color wheel is places in the light path. Depending on the expense of the DLP projector purchased, this wheel will contain from 4 to 7 segments of red, blue, and green. It spins from 150 to over 250 times per second. As light passes through a point on the color wheel, the mirrors switch in accordance with the light.When a DMD chip is coordinated with a digital video or graphic signal, a light source, and a projection lens, its mirrors can reflect an all-digital image onto a screen or other surface.

Have you ever been to homes where the people have their very own home theater projectors? Why not you? Depending on your home theater design, LCD Projectors are a typically less expensive method of getting a fantastic home cinema experience! LCD is an abbreviation of 'liquid crystal diode'. These projectors contain three separate LCD glass panels, one each for red, green, and blue components of the image signal being transferred to the projector.

As the light passes through the LCD panels, individual pixels can be electronically opened to allow light to pass or closed to block the light. This activity modulates the light and produces the image that is projected onto the screen. Since the primary colors: Red Green, and Blue make up the entire color spectrum that is visible to us, effectively modulated this technology can display a very accurate image.

Home theater projectors come close to the movie theater experience by beaming the image onto a wall or screen! They offer the largest potential picture size depending on your space. Here is some useful information about this great technology for home theater systems!

Talk about providing the biggest picture with the smallest space! Home theater projectors are a great solution for those of you who want a screen size typically bigger than what todays picture tube, rear-projection, and flat screen TVs provide. The biggest tube TVs top out at about 40" diagonally. LCD and Plasma TVs currently on the open market top out at around 70 inches, although larger ones are on the horizon.

The cost of a 70" flat screen TV as of this writing is upwards of $10,000. Now if you prefer to have a flat screen TV and do not mind the cost, then enjoy it! For the rest of you, a home theater projector may be just the ticket.

There are a few different technologies available in these devices which I will explain; however, there functionality is the same. They are:

DLP , LCD , and a larger more antiquated type called CRT .

Both DLP snd LCD Projectors are a typically less expensive method of getting great home cinema. They can range in size from about the size of 3 loaves of bread side by side to a device you can place in the palm of your hand. Those on the smaller scale are designed more for business presentations and will not likely have the features to maximize the high definition movie experience.

You can mount it on your ceiling, and aim it toward a white wall, or better yet, a screen that can be fixed, retractable, or even motorized to descend on command. The best part is, depending on your room size, seating distance from the screen, and projector, your image can be larger than 200" diagonally! Just imagine a screen so big that you feel like you are actually in a theater.

Combine this technology with the spectacular image of blu ray and the cinematic experience is simply breathtaking!




How do these technologies work? Well, there are some differences to consider:

Projector Technology:

There are three principle technologies available with variances and improvements made in all of them over the years.

• LCD Projectors
• DLP Projectors
• CRT Projectors

There are advantages and disadvantages of LCD and DLP and CRT technologies when compared to each other. Color accuracy, brightness, contrast ratio, image clarity, among many other picture attributes are constantly compared between them.


When added to home theater systems, the end result for LCD, DLP, or CRT home theater projectors is a beautiful projected image that, depending on your budget, room size, screen size, and seating distance, can rival the impact of your favorite cinema.