Lasers may become an ideal replacement for the UHP lamps, which are currently in use in projection display devices such as rear projection TV and front projectors. Current televisions are capable of displaying only half of the visible spectrum of colors.
A laser TV requires lasers in three distinct wavelengths: Red, Green and Blue. While red laser diodes are commercially available, there are no commercially available green and blue laser diodes which can provide the required power at room temperature with an adequate life time. Instead frequency doubling can be used to provide the blue and green wavelengths. Several types of lasers can be used as the frequency doubled sources: fiber lasers, inter cavity doubled lasers, external cavity doubled lasers, eVCSEL’s and OPSL’s (Optically Pumped Semiconductor Lasers). Among the inter cavity doubled lasers VCSEL’s have shown much promise and potential to be the basis for a mass produced frequency doubled laser.
A VECSEL is a vertical cavity is composed of two mirrors on top of one of them is a diode as the active medium. These lasers combine high overall efficiency with good beam quality. The light from the high power IR-laser diodes is converted into visible light by means of intra-cavity second harmonic generation. Laser-pulses with about 10 kHz repetition rate and various lengths are send to a DLD where each mirror directs the pulse either onto screen or into the dump. Because of the well known wavelengths all coatings can be optimized to reduce reflections and therefore speckle
Arasor and Novalux began work on the laser TV project nearly two years ago and found interest among TV makers who were seeking alternative technologies to plasma and LCD for flat panel displays. Consumers have favored LCD because the displays are cheaper than plasma flat screens.
Families that still watch the old-fashioned and bulky CRT (cathode ray tube)televisions also will have more choices when they are ready to upgrade. Laser technology can produce twice the color content that can be generated by LCD or plasma, said Greg Niven, vice president of marketing at Novalux, based in Sunnyvale, California, which has raised $32.2 million in two rounds since its inception in 1998.
One major claim of laser advocates is the ability to produce undiluted, perfect colors allowing precise hue mixing. With the color enhancement capable with lasers, up to 90% of the spectrum that is currently unviewable could be regained. Other improvements that laser advocates claim are bulbs that will never blow out, and increased efficiency by using two-thirds less power than traditional rear projection televisions. Historically, however, lasers have been too bulky and expensive for widespread adoption.
The laser technology advocates claim that the technology will allow displays with a richer, more vibrant color palette than the conventional plasma, LCD or CRT displays.
They also claim the displays will:
* be half the weight and cost of Plasma or LCD displays
* require around 25% of the power required by Plasma or LCD displays
* be very thin like Plasma and LCD displays are today
* have a very wide colour gamut
* have a 50,000 hour life
Look at this video for Laser-TV introduction: