Today, projectors have become as important for homeowners as they are for offices and educational institutions. They are an integral part of home theatres and are often used for gaming consoles as well. Many individuals are opting to swap their LED TVs for projectors. Images output by the projectors have a larger area and provide a cinematic and immersive experience to the viewers.
The widespread adoption of projectors has motivated their manufacturers to improve the projector technology for providing picture quality at par with the modern TVs. They also need to ensure that the lifespan of the projectors is comparable to the TVs. Laser projectors are the latest innovation in the field of projectors. These projectors output superior image quality and have a longer lifespan as compared to the projectors with lamps.
Laser projectors use lasers for creating images on a screen instead of UHP or Xenon lamps. Laser stands for Light Amplification by Stimulated Emission of Radiation. The light beam produced by the lamps in projectors scatters as it travels. It lowers the brightness of the projector and reduces the quality of the images. Even the light emitted by the LED projectors scatters though not as much as the light produced by UHP or Xenon lamps.
A laser light source emits a coherent beam of light. It tackles the scattering problem seen in lamps and LEDs. As the light rays retain their thickness over long distances, they can produce sharp images. Using a laser light source in a projector significantly improves the quality of the images output by the projector. The images are well defined, have higher brightness and sharper contrast, and appear crisp and smooth.
Laser TVs are a class of laser projectors that work on the same phenomenon but have a short throw ratio. They can produce large images even when they are placed at a distance of a few inches from the projector screen or the wall. They can perform all the functions of modern TVs.
The working of a laser projector is quite similar to UHP or Xenon projectors. Projectors have a light source like a lamp or Light Emitting Diode (LED) that produces light. The light from this source is manipulated using a display chip like DLP, LCD, or LCoS for producing images on the projector screen.
The light sources in the projectors emit white light. However, projectors require only red, green and blue colored lights for producing images. Different colored light rays have different wavelengths. Projectors use filters or splitters that block some wavelengths of the white light from the source, leaving only the red, green and blue parts of the light beam. The method is inefficient as most of the light produced by the lamp or LED is discarded.
Lasers can be designed to produce only the required wavelengths of light. They are more power efficient as they do not produce light of unrequired wavelengths like yellow, violet, purple, etc. The working of the laser projectors can be further understood by considering their different variants.
Laser projectors can use one, two or three lasers depending on the model.
RGB Three-Laser Projectors: The high-end models of laser projectors use three different lasers. Each laser produces light of a distinct wavelength – red, blue, or green. The light from the three lasers is used by the DLP, LCD, or LCoS chips in the projector to produce images on the screen. As the projectors use three different light sources, they produce images of superior quality. These projectors are designed for commercial markets and are primarily used in cinemas and theatres due to their high price tags.
Single-Laser Projectors: The most affordable laser projectors make use of a single laser system. It lowers the cost of the projector as the number of lasers used is less, making the projectors ideal for the consumer segment. The projectors use a single laser that emits blue light. The light beam output by the laser is then split into two distinct blue beams. One of the resulting beams then goes on to hit a yellow phosphors wheel. The wheel emits a yellow light as its phosphors compound is excited by the blue light beam. The yellow light beam is then split into red and green beams using dichroic filters. The other blue beam of light resulting from the initial split is then passed onto the DLP chip along with the red and green beams produced by the dichroic filters. The chip uses the three light beams to produce the final image.
Two-Laser Projectors: Some brands employ two lasers in their projectors to improve the quality of the images. These projectors have two lasers both of which emit blue light. The light from one of the blue lasers is used to energize the yellow phosphors wheel to produce yellow light which is then split into red and green light using dichroic filters. The blue light beam from the second laser is reflected onto the display chips along with the red and green light beams from the dichroic filters for producing the images on the projector screen.
RB Laser Projectors: RB projectors use lasers that emit red and blue light beams. The projector has a green phosphors wheel instead of a yellow one. The blue and red colors of the image are produced by using the light beam from the lasers while the green beam is emitted by the phosphors wheel when it is excited by the light from the blue laser. The display chips of the projector combine the three light beams for producing the images. RB laser projectors provide excellent color reproduction as compared to the projectors that use only blue lasers.
Hybrid-Laser Projectors: A few brands also manufacture hybrid laser projectors. These projectors use a laser for producing the blue light beam. However, they also contain an LED for producing the red light beam instead of a laser. The blue light is split into two beams, one of which is directed onto the display chips and the other is directed onto the green phosphors wheel. The phosphors compound on the wheel gets excited and produces a green light beam. The red light from the LED is also reflected onto the display chip which then produces the final images using the three beams. The red LED helps to improve the color of the images output by the projector while keeping its cost low.
Projectors with a single laser source generally use a single display chip. Projectors that have more than one laser, often employ 3-chip DLP, LCD or LCoS technologies.
There are many advantages of the laser projectors when compared to the lamp or LED projectors.
Comparatively Higher Brightness – Laser projectors have a higher lumens rating than the lamp projectors with the same wattage. A 300-watt laser projector will produce brighter images than a 300-watt lamp or LED projector. It is because the majority of the light output by a lamp projector is blocked or absorbed while the lasers only produce light rays of the required wavelength. The brightness of the lamp projectors also degrades over time which is not the case in laser projectors.
Color Quality – Laser projectors support a wider range of color gamut. Color gamut defines the percentage of the colors that a projector can produce out of the total colors perceivable by the human eye. Laser projectors support a color gamut of up to 90% and yield images with near-precise colors.
Superior Quality Images – Laser projectors output superior quality images as the light emitted by the lasers is coherent and does not scatter like the light from lamps and LEDs. The light can retain its thickness over long distances without suffering a significant loss in quality.
Low Power Consumption – The amount of power consumed by lasers is less as compared to UHL or Xenon lamps conventionally employed in projectors. Hence, laser projectors consume less power as compared to their counterparts with lamps. The amount of heat generated by the laser projectors is also less.
Fast Start – Lamp projectors take time to turn on or off as the lamp has to warm up before use and cool down afterward. It is a major quirk in lamp projectors which most users find annoying. Laser projectors do not have the same limitation as they can be turned on or off almost instantly.
Longer Lifespan – The lamps used in projectors typically have a lifespan ranging from 3,000 hours to 10,000 hours. They must be replaced at the end of their lifespan. Lasers used in the projectors are rated for more than 20,000 hours of operation which is a lot more than the projectors with lamps. The long-life of the laser projectors offsets their high initial cost.
The main disadvantage of the laser projectors is their price. Laser projectors are far more expensive than halogen or Xenon lamp projectors. You can buy multiple halogen projectors for the price of a single laser projector. Most people may not be willing to spend such an amount on a projector.
Laser projectors are becoming popular with the emergence of innovative technologies in projectors. There is a wide range of laser projectors available from different brands. These range from the low-cost single laser projectors to the top of the line RGB three-laser projectors.
Many brands have also started manufacturing Laser TVs which are essentially laser projectors with short or ultra-short throw ration. They can output large images at a distance of a few inches from the projector screen or wall. There is no need to install them, and they can be kept on a table just like TVs. Many homeowners are substituting their LED TVs for laser TVs.
The superior quality of the images output by the laser projectors makes them the ideal choice for offices as well as professionals. Their low power consumption further shifts the scales in their favor. Laser projectors pack numerous advantages and provide superior picture quality as compared to the lamp and LED projectors. Their lowering costs are putting them within reach of most consumers. It is safe to say that laser projectors are here to stay.