In the future, I expect the familiar projection bulbs that we have used for decades will be phased out and replaced by laser/LED technology, as this light source puts out much less heat and are quieter, allowing for more placement options.
Len Calderone for | AVSystemsMag
Why should you consider a laser projector? This technology is capable of some really impressive images. Lasers are an ideal replacement for the UHP lamps that are currently being used in projectors. Lasers have a lifetime potential of 25,000 hours, compared to 10,000 hours for a UHP lamp.
Using laser technology, a projector has a high depth of field, allowing images to be projected on most surfaces even though the surface might be uneven. The sharpness, and contrast ratio are higher than those of other projection technologies. The on-off contrast ratio of a laser projector is typically 50,000:1 or higher, while DLP and LCD projectors usually have a contrast range from 1000:1 to 40,000:1. In comparison to conventional projectors, laser projectors provide a lower lumen output, but because of the extremely high contrast, the brightness actually appears to be greater.
But what is a laser? A laser is a device that controls the way that energized atoms release photons. Laser is actually an acronym for "light amplification by stimulated emission of radiation," which describes very concisely how a laser works. Laser light is very different from normal light. The laser light that is released is monochromatic. It contains one specific wavelength of light (one specific color), which is determined by the amount of energy released. The light released is consistent as each photon moves in step with the others. Laser light is very directional with a very tight beam and is very strong and concentrated.
Photons, with a very specific wavelength and phase, reflect off mirrors to travel back and forth through a lasing medium. In the process, they stimulate other electrons and can cause the emission of more photons of the same wavelength and phase. A cascade effect occurs, and soon there are many propagated photons of the same wavelength and phase. A mirror at one end of the laser is half-silvered, meaning it reflects some light and lets some light through. The light that makes it through is the laser light.
A laser projector utilizes individually modulated laser rays of different colors to produce a combined spot that is scanned and projected across the image plane by a polygon-mirror system. The system works either by scanning the entire picture a dot at a time and modulating the laser directly at high frequency, much like the electron beams in a cathode ray tube, or by optically spreading and then modulating the laser and scanning a line at a time. The line itself is modulated in much the same way as with Digital Light Processing (DLP).
Lasers are used as a light source for DLP or LCOS imaging technology in conjunction with LEDs. A laser/LED light source is more cost-effective than the older lamps, and last longer. Laser/LEDs really come into their own where you want to avoid changing lamps. Some projector manufacturers claim that laser/led light sources last 20,000 hours.
LEDs are illuminated by the flow of electrons. LEDs do not have a filament, like regular bulbs, and therefore last much longer. The lack of filament also allows the LEDs to operate more efficiently than traditional bulbs. They do not get as hot and require far less electric power. LED light sources are mercury-free and can power off and on instantly. They do not require a fan to control their operating temperature, and therefore allow for quieter and smaller projectors. LED projectors are typically not as bright as those powered by other light sources at this time.
The Sony VPL-FHZ55 was the first 3LCD laser projector. This projector is perfect for a wide range of installation needs, producing bright, detail-packed WUXGA (1900 x 1200) images. You'll see the difference in image quality with Sony's BrightEra technology and 4000 lumens.
The Sony VPL-FHZ55 has generous zoom, throw and lens shift adjustments, which give more flexibility for positioning the projector where you need it, whether it be close to the ceiling, near the screen or even horizontally offset. The throw ratio can be extended even further with a choice of optional lenses.
The image can be projected onto non-flat surfaces with Image Warping, which corrects the image geometry for natural-looking projections – even on convex or concave surfaces. The laser output adjusts automatically, depending on picture content, which saves energy when dark scenes are being projected.
The Panasonic PT-RZ470 uses a laser/LED light source and is maintenance free for 20,000 hours. Panasonic has improved the projector usage experience for educational institutions as well as professional applications, such as museums and digital signage.
1080p resolution, plus Panasonic's HDBaseT technology, projects full-HD resolution with 3,500 lumens of brightness. The instant on/off function reduces unnecessary projection and saves energy during presentations.
The PT-RZ470 is equipped with Panasonic’s proprietary Daylight View technology, which allows a built-in ambient light sensor to match the image quality according to the ambient conditions. The PT-RZ470 turns on and reaches full brightness virtually instantaneously without any need for warm up time. It can be turned on and off without any limitations, as well as operate 24/7.
The ViewSonic Pro9000 projector is a full HD 1080p laser/LED hybrid projector ideal for home theater. This projector is equipped with TI DarkChip3 technology to deliver excellent colors and razor sharp images with 1,600 ANSI lumens and 100,000:1 ultra-high contrast ratio. Built with the advanced hybrid light engine, the Pro9000 is a lamp-free projector that can operate 20,000 hours with filter-less design making it virtually zero maintenance.
The Pro9000 comes standard with dual HDMI for connecting to 1080p devices, audio out for attaching external stereo speakers and RS232 for centralized remote control capability. Home theater enthusiasts can count on the Pro9000 full HD 1080p laser/LED hybrid projector to project stunning movie-like visual experiences.
Another projector, using the hybrid laser/LED light source with DLP technology is the Casio XJ-H1700. The 1024 x 768 resolution and 4,000 lumens make for a great commercial projector. As with the other laser/LED projectors the XJ-H1700 will go 20,000 hours without a lamp change. The lamp puts out 4,000 lumens while only consuming 1 watt in standby mode.
The XJ-H1700 has two RGB, RGB output, video, HDMI, RS-232, audio in/out, and is DLP 3D ready.
If you are interested in a Pico/Micro projector, the AAXA P300 is the world’s brightest battery-powered pocket projector. The P300 features a revolutionary new compact optical engine capable of delivering 300 peak lumens at a high-definition (HD) resolution of 1280 × 800. Powered by Texas Instruments’ DLP Technology, the AAXA P300 employs Vibrant Color LED technology that delivers dazzling color quality with an operating life of more than 15,000 hours and is capable of generating a viewing experience of up to 120 inches.
The P300 is a true “pocket projector” at less than 5.9” long, 3.9” wide and 1.6” tall. It is both compact and energy efficient, consuming less than 25 watts when plugged in. Additional features include adjustable tripod, 1280 x 800 VGA input support, 1280 x 800 HDMI support, Micro SD Card slot, USB port, composite video input, and 3.5mm headphone jack.
The P300's LED light source lasts 10 times longer than conventional lamps so bulb changes are a thing of the past. The P300's optional lithium ion battery gives upwards of 60 plus minutes of operation and is rechargeable and long lasting, making it a truly portable device.
This is just a sampling of laser technology in projectors. There are many more models available.
In the future, I expect the familiar projection bulbs that we have used for decades will be phased out and replaced by laser/LED technology, as this light source puts out much less heat and are quieter, allowing for more placement options. They will also eliminate many service calls, and not need constant recalibrating for top picture quality.
Also, lasers have considerably higher brightness, better contrast and wider color gamut compared to traditional projector lamps. Look forward to a brighter projection experience
Len Calderone - Contributing Editor
He also writes short stores that always have a surprise ending. These can be found at http://www.smashwords.com/profile/view/Megalen.
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