|
Projection Technology
First things first, not all projectors are created equal. There are two main projection technologies: LCD (Liquid Crystal Display) projectors and DLP (Digital Light Processing) projectors. The large majority of projectors that are on the market today feature either LCD or DLP technology.
In addition, there is a third projection technology called LCOS (Liquid Crystal On Silicon) that is quickly emerging as an alternative to DLP and LCD.
Now that you know the three main types of technologies, what does each technology do, and what are the advantages and disadvantages of each?
LCD technology is the oldest and most widely used technology of the three. LCD technology uses three glass panels inside the projector that separate the color spectrum into red, green, and blue. The light passes through these panels and creates the image on the screen.
DLP technology is a much newer technology than LCD, but has made great strides in the past five years to challenge the LCD market share. DLP is a proprietary technology developed by Texas Instruments. DLP technology takes the light from the lamp, reflects it off of thousands of tiny spinning mirrors and through a color wheel, which then makes up the image.
LCOS technology is one of the newest technologies to surface in the projector industry. Think of it as a hybrid between LCD and DLP technology. It is a reflective technology that uses liquid crystals instead of individual mirrors. In LCOS, liquid crystals are applied to a reflective mirror substrate. As the liquid crystals open and close, the light is either reflected from the mirror below, or blocked. This modulates the light and creates the image.
Although it might help to understand the differences in technologies, the best way to determine which technology you need is to learn about the advantages and disadvantages of each.
Back to top
Advangtages of LCD Technology
Color Saturation. LCD projectors typically have better color saturation, which means that the colors are deeper and more vibrant. Historically DLP projectors tended to produce colors that were a little washed out. Today, many DLP home theater projectors have a six-segmented color wheel. This improved color wheel greatly improves the color saturation. However, if you put a DLP projector next to an LCD projector and projected the same image or video, most people would say that the LCD projector had better color saturation.
Detailed Images. Not only is the color better in an LCD projector, images and data are more detailed. LCD can usually deliver a slightly sharper image than DLP at any given resolution. The difference between the two is noticeable in the display of material like detailed financial spreadsheets. However, there is no visible difference in sharpness with video.
Brightness. If you need a very bright projector (3000 lumens or more), an LCD projector is probably your best choice. DLP isn't a very light efficient technology, therefore there are only a very few 3000+ lumen DLP projectors on the market. You'll find dozens of LCD projectors that range from 3000 lumens to more than 6000 lumens. Plus, a high-lumen LCD projector will be far less expensive to a comparably bright DLP projector.
Back to top
Advangtages of DLP Technology
Less Visible Pixels. The main reason that many home theater enthusiasts prefer DLP technology is because with DLP technology, there is less visible pixilation. In the past, you could see a "screen door effect" when viewing video from LCD projectors. This effect was due to the pixels that were visible across the entire screen. Today's LCD projectors have reduced the pixilation to make video comparable to DLP, however DLP's pixels are still less visible.
Contrast Ratio. Another reason that DLP technology has been adopted by many home theater enthusiasts, is because it is capable of producing higher contrast ratios than a comparable LCD projector. Contrast ratio is the measure of how black the black levels look on video. While there are more DLP projectors on the market with higher contrast ratios than LCD projectors, LCD projectors are now closing the gap. Today, you can find many LCD projectors with great contrast ratio.
Portable Projectors. One more advantage of DLP technology over LCD is that DLP projectors can be much smaller than LCD projectors. Since the DLP light engine consists of a single chip rather than three LCD panels, DLP projectors tend to be more compact. Most projectors under four pounds are DLP projectors. If you need a micro-portable projector, you should look at DLP.
Rainbow Effect in DLP Projectors
If there is one single issue that people point to as a weakness in DLP, it is that the use of a spinning color wheel to modulate the image has the potential to produce a unique visible artifact on the screen commonly referred to as the "rainbow effect."
Not everyone, however, sees the rainbow effect. In fact, most people cannot detect color separation artifacts at all. However, for some who can see the rainbow effect, it is so distracting that it renders the picture literally unwatchable. Others report being able to see the rainbow artifacts on occasion, but find that they are not particularly annoying and do not inhibit the enjoyment of the viewing experience.
With today's faster spinning, six-segmented color wheel DLP projectors, the reported problems of rainbow effect have dropped dramatically. So it is not nearly the problem that it once was.
Back to top
LCOS - Liquid Crystal on Silicon
LCOS-based projectors typically use three LCOS chips, one each to modulate light in the red, green, and blue channels. In this it is similar to an LCD projector which uses three LCD panels. Both LCOS and LCD projectors deliver the red, green, and blue components of the light to the screen simultaneously. There is no spinning color wheel used in these projectors as there is in single-chip DLP projectors.
LCOS technology is usually a very high resolution, and typically higher in price than most LCD and DLP products. Most all LCOS projectors are in the SXGA (1365x1024) resolution class and higher. So by definition they are not cheap.
LCOS Advantages
No Visible Pixels. As a result of the extremely high resolution, there are no visible pixels on the screen when projecting from an LCOS unit. If you want an image as smooth as silk (but more costly than cashmere), LCOS is your best solution.
Rich Colors. Like LCD technology, LCOS technology also delivers rich, saturated colors. Brilliant colors plus pixel-free images equals pristine video that will impress most anyone.
No Rainbow Effect. Forget about getting headaches or having trouble watching a video. Because LCOS is more similar to LCD technology, there is no rainbow effect.
LCOS Disadvantages
Low Contrast Ratio. The primary weakness with LCOS technology, besides the high price tag, is a lack of contrast ratio. Most LCOS projectors fall in the range from 500:1 to 800:1; much less contrast ratio than most DLP projectors.
Limited Lamp Life. Most LCOS projectors have a limited lamp life in the 1000 to 1500 hour range.
So not only are you paying a lot for the projector, you'll also be spending more at lamps since most projector lamps last 2000 hours or more.
Whew. That was a lot of information. So now you're ready to buy a projector? Not quite, we've just scratched the surface.
Back to top
Brightness
Projector brightness is measured in ANSI lumens. The lowest lumen projectors today start at about 700 lumens and go up to a jaw-dropping 15,000 lumens. When it comes to purchasing a projector, the two biggest factors that affect the price are 1) Resolution and 2) Brightness.
So if there is such a variance in brightness, how will you know if you are getting a bright enough projector for your application? Your best bet is to call one of our qualified sales consultants. They'll ask you all of the fact-finding questions that they need in order to make sure that you get enough brightness in your projector. A good rule of thumb is that it is always better to err on the side of too many lumens than too few. This guide will also give you a starting point to determine the projector brightness that you need.
In order to determine how bright of a projector that you need, you will need to weigh three factors: Size of room, Size of audience (specifically the distance from the screen to the farthest seat), and amount of light in the room.
Size of room / Size of Audience. Where will you be using the projector most of the time? If you'll be using the projector most in an office cubicle or small office, you may be able to get away with 1000-1500 lumens. If you're projecting in a classroom and will have control of the lighting, 1000-1500 lumens should also work. For an average size training / conference room, we recommend starting with at least 2500 lumens for your projector. If your conference room will hold more than 150 people and is moderately large, consider a projector of at least 3500 lumens. The same advice holds if you will be projecting in a college auditorium. If you will be projecting in a church, we also recommend a projector of at least 3000 lumens, unless the sanctuary is unusually dimly lit.
Amount of Light. Nothing kills a projected image quicker than light. Artificial light can be controlled in most environments. Even if you have to turn the lights off to improve the image, at least you have an opportunity to improve the image. Ambient light (sunlight) is one factor that can certainly make an image suffer and a presenter sweat.
Determine where you will be using the projector in most cases. If the room has bright fluorescent lighting that you can't dim, add 1000 lumens to the projector that you were considering. In other words, if 1500 lumens would be fine with the lights out, get a 2500 lumen projector so you can present with the lights on.
In business, turning off the lights makes it difficult or impossible to take notes. In school, killing the lights kills attention spans of students (and puts a few to sleep). So you should always aim to present with some sort of lighting.
A couple of ways to beat heavy lighting is to put the lights on a dimmer switch. Another way is to turn off the lights (or take out the bulbs) that are closest to the screen. Even in a bright room, a projected image will look remarkably better if there is no direct light on the screen.
To curtail the effects of sunlight in your presentation room, you'll obviously need shades, blinds or room darkeners on the windows. If you still cannot reduce the amount of ambient light in the room, you will need to increase the brightness on the projector you are looking to buy to 2000 lumens or more.
These guidelines are a foundation to determining the level of brightness that you need in the projector. But, a call to one of our sales consultants is the best way to make sure you don't pay for lumens that you don't need, and that you get every lumen that you do need.
Back to top
Projector Weight
The third main factor besides resolution and brightness that determines the price of a projector is its weight. Projectors today start at a miniscule sub-two pounds to behemoth 75 pounds or more. The majority of all projectors sold fall into the 6-12 pound range. Since projectors that are below four pounds tend to cost more because of their weight advantage, many presenters buy projectors in this 6-12 pound range.
A 6-pound projector is comparable to the weight of a laptop. If lugging a laptop in a shoulder bag isn't too difficult for you, opt for a projector that is around 6 pounds. If you need more than 2500 lumens of brightness or extra features, you'll probably be looking for a projector in the 8-12 pound range. These projectors are a little more robust, and probably ship with a standard projector case rather than an over-the-shoulder case.
If portability isn't an issue, and you will be installing the projector, look at projectors that meet your lumen and feature requirements first. You might end up with a projector that is over 12 pounds, but has all of the bells and whistles that you wanted.
Back to top
Warranty Considerations
Repair or Replace Warranty. This is one of the best warranties and is offered by several manufacturers. Call your AVPartner sales consultant today to find out which manufacturers offer this warranty and which do not. Simply put, if your LCD projector is not working, an A/V technician will try to offer a solution or repair the projector over the phone. Once the audio-visual technician determines what needs to be done, the technician will come to your business or home to fix it. If the technician cannot fix the LCD projector, the manufacturer will replace the projector with a new one.
Return to Base Warranty. This type of projector warranty is the most basic warranty as well as the most common. The way it works is if the data projector is not working, you have to pack it up and return it to the manufacturer. The manufacturer will repair the data projector and send it back to you. The average repair time is 2 to 3 weeks. You could be looking at a longer wait because the repair parts might be on backorder. Check with your AVPartner sales consultant to find out what the average repair time is for the manufacturer.
Swap-Out Warranty. The Swap-Out Warranty is probably the best type of projector warranty, but is rare. With this warranty, if your digital projector is in need of repair, a technician will first determine the problem over the phone. Next, you can send the digital projector to the manufacturer to fix and at the same time, they will send to you a loaner projector to use while yours is being repaired. You usually receive the loaner projector the next business day. The loaner projector is typically a used projector, but it will work well until you get your projector repaired. Obviously, once you get your original digital projector back from the manufacturer, you are responsible for returning the loaner projector.
Dead on Arrival Warranty. Several projector manufacturers offer a projector warranty protecting you if you plug in your new multimedia projector and it does not work. Purchasing a projector that doesn't work when you get it is rare, but it does occasionally happen. With the Dead on Arrival Projector Warranty, you simply return the non-working projector and the manufacturer will rush another new model multimedia projector to you.
Projector Lamp Warranty. Lamp warranties range from 30 days to 6 months. If you are putting your digital projector into a rigorous environment, it may be worthwhile to find a projector with a better projector lamp warranty. Some very inexpensive projectors come with lamp warranties that can be as little as 30 days. Look at this carefully when choosing a digital projector, because the immediate savings may result in a hefty repair cost down the road.
Back to top
Extra Projector Features
If you get a projector with the right resolution, good brightness, decent weight and a solid warranty, you're ahead of most projector buyers. However, there are a few additional key features to keep in mind that will make presenting easier and more successful.
Wireless projectors. Wireless projectors are becoming more widely available as more people are using wireless in their laptop computers and other technology. The main benefits of projecting wirelessly are as follows:
1. Cabling issues are eliminated which makes your workspace tidier, less confusing, and signal loss through cabling is no longer a problem.
2. Another advantage of projecting wirelessly is that you can switch between multiple PC servers easier.
3. An additional advantage of wireless projectors is that the presenter will also be able to have better mobility while presenting without walking around or tripping over wires.
Digital Zoom. Most projectors have a zoom lens, allowing the adjustment of the image size without moving the DLP or LCD projector. A projector with a zoom factor of 1.2x will allow you to adjust the picture by only 20%. Look for a DLP or LCD projector with a higher zoom, as it will allow you to present an image that will match most any screen size.
A digital zoom lens on a projector allows you to further move into the frame by having the DLP or LCD projector continually resize the image. It is a nice feature to have in conjunction with manual/power zoom because as you move into the frame, the screen size remains the same.
Keystone Correction. A projector lens is made to shoot above the projector. Because of this, the projected image becomes skewed when the projector is titled up or down. This skewing of the image is called keystoning. Keystoning has been an issue with projectors since the first projector rolled off of the assembly line. Thankfully, every projector today has a feature that will correct this physics snafu. Appropriately enough, it's called Keystone Correction. There are three types of keystone correction in projectors:
Fixed keystone correction is when a projector lens shoots the image higher than the lens so the projector itself doesn't block the viewer's line of sight.
Digital keystone correction enables the user to digitally correct keystone problems if the projector must be tilted further upward or downward than the fixed keystone position.
Auto keystone correction is just like digital keystone correction, but better because the projector automatically corrects for keystoning every time you tilt or shift the projector. This feature is becoming more popular on several projectors today.
PCMCIA Card. This feature allows you to give presentations without a computer. Microsoft PowerPoint and Lotus Freelance Graphics presentations can be downloaded to a memory card (PCMCIA) which the projector then uses to display the presentation. A useful feature is that you can save different presentations on different PCMCIA cards if more than one person will be using the projector.
The only drawback with the PCMCIA card is that it only displays still images. The memory capabilities cannot display PowerPoint slide transitions, animations, MPEG movies, or sounds. You can still connect your computer and video recorder to the projector for other presentations as well.
In my experience, this is one of those features that sound great when you go to purchase the projector, but in reality it's seldom used. Before you pay a little extra for a projector with a PCMCIA Card, determine how much you and others would actually use it.
Lens Shift. Imagine installing a projector with your eyes closed. You could probably get away with that if you have a projector with l ens shift. With lens shift, you aren't relegated to moving the projector box to square the image on the screen. All that you have to do is shift the lens horizontally or vertically to get the best image possible. This gives you greater flexibility in installing or setting up the projector. Rather than spending a couple of hours installing the projector, you could spend three minutes and the rest of the time watching a good movie.
Back to top |
