Projector Buying Guide

Benefits of a Projector (back to top)

Projection (in television terms) unbinds the viewing experience restricted by the physical constraints imposed by a TV tube. A projector can fill the entire wall of your living room making it your own personal theater screen. Movies can be enjoyed as they should be in the auditorium of a cinema. The entire audio/video playback is handled by decoding equipment which then routes the video information to the projector, finally to be projected on to a blank screen. The audio playback, though, would still need some sort of external amplification for surround sound effect or to fill up larger rooms.

1. How Projectors Function (back to top)

There are two different types of projectors; the first one is a simple Cathode Ray Tube (CRT) projector and the other is based on Liquid Crystal Projection (LCP) technology. Each category differs in terms of installation and performance.

The CRT method involves generating the final image by initially splitting the original image into the core RGB (Red, Green and Blue) spectrum of colors. The actual image is then made available in three different hues of the same spectrum. Each of these images is then reproduced by 3 small CRT tubes, one each for each color, in front very powerful refractive lens. Again, each CRT has its own refractive lens; totaling three. These lens together focus in such as way, that the resultant focus recreates an enlarged image on a blank screen. Such projectors are most common at movie theaters or at public display areas such as: malls, airports, etc.

The LCP based projection models feature three simple and small, distinct liquid crystal panels. The image is decoded into the basic RGB (Red, Green and Blue) spectrum and is reproduced by the LCP panels. The light from a high-wattage metal halide lamp passes through a complex series of dichroic reflectors and filters. This apparatus splits the pure white spectral light into three distinct lights of red, green and blue. The three light rays, then bounce off the image so created by the LCP panel towards a single lens that converge the rays to a pre-defined focal point. The lens is constructed to allow changing of the focal point for sizing and placing the image at variable lengths and measuring dimensions.

The LCP technology is implemented by the use of four different methods: Standard LCD, Polysilicon LCD, DLP (Digital Light Processing), Liquid Crystal on Silicon (LCOS or LCoS).

• Standard LCD (back to top)

The simplest of LCP projectors - an LCD (Liquid Crystal Display) projector uses three separate LCD glass panels, each representing either of red, green, and blue components of an image/video signal. A special Halogen lamp produces a high intensity light beam onto a prism. This prism splits the basic light wave in to the three component colors: red, green and blue at very high luminescence. Each colored light passes through the LCD panel matching its own shade to finally pass through a large refractive lens. The lens then focuses the three light beams onto a single area to reproduce the original image in larger dimensions.

 

• Polysilicon LCD (back to top)

An evolved version of the basic LCD projector, a Polysilicon projector, uses LCD panel of a higher density of pixels with even higher color saturation than the standard LCD panel. The basic mechanism remains the same.

 

• DLP (Digital Light Processing) (back to top)

An advanced method of projecting images, a digital light processing projector recreates the entire image by modulating the lamp's light by manipulating the angle and focus of thousands of micro mirrors located on a single microchip. As little as 400,000 micro mirrors modulate light from a lamp and project the 'modulated' signal out through the lens onto the screen. A single pixel is draw by a single mirror out of the entire gamut of pixels lined up on the matrix designed on the semiconductor chip. This type of projector can easily support resolutions of: 800x600, 1024x768, 1280x720, and 1920x1080 (HDTV) formats. Gaining popularity among the masses, this technology is usually referred to as DMD (Digital Micromirror Device).

 

• Liquid Crystal on Silicon (LCOS or LCoS)(back to top)

This newly invented technology is called 'micro-projection' or 'micro-display' technology and uses liquid crystals instead of individual mirrors. Much like the DLP projection technology, the liquid crystals are transfixed directly to a silicon chip, the surface of which is coated with a highly reflective, aluminized, passivation layer. This technology supports higher resolution reproduction of images using highly advanced silicon technology compared to liquid crystal display and plasma display technologies, which makes it less expensive to implement in such devices.

 

2. Purchasing Criteria (back to top)

Choosing the right kind of projector depends upon determining the nature of use. Certain projectors may give excellent visual quality but have certain limitations such as the number of hours that the device can be put through constant use. The overall quality of the projected image may deteriorate as the high intensity lamp beneath the image reproduction system melts the pixel arrays over a period of time. Hence, consumers should evaluate projectors depending on the duration and type of use. The following criteria will lay down the parameters in deciding upon the best suited projector system:

• Type of Projection Technology (back to top)

For regular usage of medium quality graphics such as Video CD movies, normal desktop projection, simple presentations, etc. a Standard CRT or an entry level LCD projector may be best suited to such tasks. The CRT projector can last longer during the day without affecting the visual quality at any given time. Though, it may require additional cooling due to the multiple CRT units generating high luminosity beams from each of them. The high temperature may damage the internal circuitry that decodes and splits the digital signal into three color beams. This type of projector costs significantly less for small sized projection needs, and significantly higher for large sized projections.

 

The LCD type of projector, quite different from a CRT based projector, works much more efficiently generating lesser heat. Yet, at the same time, it produces excellent quality images at higher resolutions with richer colors. This type of projector cannot last throughout the day (around 8 to 10 hours max.) due to the highly sensitive nature of the LCD pixels array. The pixels tend to 'melt' due to the intense heat generated by the Halogen lamp. An LCD display usually can generate light measuring an intensity of 1,000 to 2,000 lumens. This makes it quite efficient at display crisp and bright images for small screen sizes in small business rooms or classrooms.

 

The DLP or LCoS projectors belong to the high-end category of projectors. They can produce vivid colors at high resolutions with a minimum brightness measuring above 2,000 lumens. They are mostly suited for large sized conference rooms or classrooms. They can produce images of resolutions up to: 800x600, 1024x768, 1280x720, and 1920x1080 (HDTV) formats, making them quite an attractive choice for large sized companies and educational institutes. These projectors generate comparatively lesser heat and last longer than LCD projectors and can be used for periods longer than 10 hours per day. The underlying lamp deteriorates over a period of time, demanding an expensive replacement. DLP projectors can produce 16. 7 million colors using a single chip DLP system. A three-chip DLP projector system is capable of producing 35 trillion colors.

 

• Resolution (back to top)

To determine the resolution of the projector, chart out the type of activity expected form the projector. If the main use of the projector is displaying Power Point style graphics, charts, graphs, and general business presentation, do not purchase expensive, extra high resolution equipment (ex. a DLP projector). A projector supporting SVGA resolution would suit this kind of task, and is likely to fit your budget better. However, if often presenting materials like Excel spreadsheets with a lot of numerical data on the screen, you will probably be happier with XGA resolution.

 

• Brightness (back to top)

When deciding how much brightness your projector should emit, consider the darkness of the rooms. Typically, the more light in the room or the farther the projection screen away your setup, the brighter the lamp should be.

 

3,000 lumens and more - the ultra-bright projectors can deliver brightness levels ranging from 3,000 up to 12,000 lumens or even more. They are used in large venues such as: board rooms, conference rooms, training rooms, auditoriums, churches, concerts, nightclubs, etc.

 

2,000 to 3,000 lumens - These projectors form the high-performance portable and semi-portable range of projectors. Products in this class are suitable for large conference rooms and classrooms. They also offer more flexibility in terms of audience size since they can illuminate a larger screen sustaining much lower quality loss of image.

 

1,000 to 2,000 lumens - Projectors in this range strike a perfect balance between performance and price. They are suitable for use in normal business conference room and classrooms.

 

1,000 lumens and less - A tight budget user will likely find the most benefit from a projector with lowest light-output. The only drawback is to maintain absolute dark ambience in the projection room to make your presentations so that the image on the screen is not washed out.

 

• Weight (back to top)

If the projector is intended to be mounted in a board room or carted from office to office the projector's weight isn't going to be an important concern. However, for making an on-site sales presentation, a light-weight projector makes more sense. The lightest of the models weigh at just below 5 pounds. While ultra-light series weigh even lesser.

 

• Extra Features (back to top)

Additional cables, wires, ports, remote controls, composite video inputs for connecting DVD players or HDTV tuners, digital zoom functions, etc. all add up to additional benefits for you, the user. Importantly the lamp life should be at least a couple of hundred hours for prolonged usage and reduce infrequent expenses for changing it. The life expectancy of low end halogen lamps is rated to be around 40 to 70 hours of use. High-end, high quality, lamps can last up till 400 hours of projection life time.

 

 

3. Making the Decision (back to top)

While owning a projector and using it for personal use is fairly simple, acquiring one can be quite a daunting task. You can check out various models built around numerous different technologies such as LCD, DLP, etc. at a comparison shopping site such as www.smarter.com. There you can compare prices and features across models and also check among several other suppliers over the Internet. Additionally, you might consider checking out a live demonstration at the nearest show room or outlet for a live demonstration of a particular projector's quality.

Buying a good projector requires investment of a reasonable amount of time in researching and evaluating the various contenders. The trick is to strike the perfect balance between price and functionality; and the best way to begin is to find out exactly what your needs are. Hopefully, you now have more information to help make your purchasing decision more informed, now go find a great projector!