Caren B. Les, email@example.com
LYON, France – Picoprojectors will drive
the green laser market – expected to reach about $500 million in revenue by
2016, up from an estimated $20 million in 2011 – with more than 45 million
devices, according to a market analysis by Yole Développement sarl.
The emerging microprojector technology has applications in mobile
phones, digital cameras, media players, personal digital assistants, head-mounted
or head-up displays, laptop computers and other portable devices, enabling users
to project the smaller image from their device onto a wall or other surface so that
it may be easily viewed or shared in a larger format. The technology – stand-alone
or embedded – requires delivery of a high-quality image and may allow the
projection of movies, video games or even touch-screen menus.
In the microprojector market, lasers would be the ideal light-emitting
device because of their ability to deliver highly saturated colors in the widest
possible gamut, according to Yole’s report, Green Laser Market for Projection
Devices. Published in April 2010, it comprises a market analysis of direct- and
indirect-emitting semiconductor green laser diodes in projection applications. Lasers
offer focus-free operation and are expected to deliver improved wall-plug efficiency,
which will affect the power consumption for battery operation, the company said.
There are three vastly different technologies battling for the
heart of the picoprojector: liquid-crystal-on-silicon microdisplays, digital light
processing devices and scanning mirror systems (also called laser beam-steering
systems), according to an article in the May 2010 issue of IEEE Spectrum titled
March of the Pico Projectors by Jacques Lincoln, global product manager for automotive
displays at Microvision Inc. in Redmond, Wash. He wrote that the imagery of the
scanning mirror systems is extremely sharp, has the highest contrast of the three
technologies and potentially could be produced in the smallest package.
Red, green and blue lasers are required for the laser-based microprojector.
The report from Yole notes that the light-engine module, including the light engine
and the scanning device, is expected at a target price of $40 to $70, depending
upon the application, implying a laser price target of $10 per color. Neither blue
nor green lasers currently meet these price requirements, the report states.
Green lasers have niche applications in industry, medicine, defense
and biomedical instrumentation, all of which can work with existing solid-state
lasers or the more recent combinations of semiconductor lasers with nonlinear crystals,
according to Yole. The company said that three green laser semiconductor-based technologies
are frequency-doubled diode-pumped solid-state lasers, second-harmonic generation
of semiconductor edge- and surface-emitting lasers, and direct-emission laser diodes.
It indicated that the technology will undergo development from second-harmonic generation
to direct-emission sources.
Green laser developments
Various companies have been developing green laser technology
for applications in microprojection; e.g., a green laser employing quantum dot semiconductor
crystals was developed by QD Laser Inc. of Tokyo in collaboration with Yasuhiko
Arakawa of the University of Tokyo’s Institute for Nano Quantum Information
Electronics. QD Laser said in a September 2009 press release that the compact laser,
which operates with low power consumption, is optimal for use in projectors that
can be mounted on mobile phones or laptop computers.
The company said that it produced the green laser by applying
distributed feedback laser technology to create a quantum dot semiconductor crystal
laser operating at 1064 nm. The photon stream is then filtered through a nonlinear
crystal via second-harmonic generation, forming photons with a 532-nm wavelength,
half the original. The green laser can be housed in a generic TO-56 package operating
from a 2-VDC supply.
Michael Usami, vice president of sales and marketing, said that
the company is sampling the green laser by targeting mass production by the end
of the year. He added that the green laser is suitable for any mobile projection
system – especially for flying spot-type scanning systems, which require high-speed
modulations – or for applications that require high beam quality.
“If green lasers can be mass-produced with reasonable pricing
and enough manufacturing capacity, red-green-blue small-projection engines would
be realized and would enable the creation of brand new applications. We would like
to contribute them,” Usami said.
As announced in an August 2009 press release, Osram Opto Semiconductors
GmbH of Regensburg, Germany, achieved a direct-emitting green InGaN laser with 50
mW in its laboratory. Suitable for mobile laser projection, the diode emits a true
green, defined by the spectral range of 515 to 535 nm.
Direct green InGaN-based laser emission with CW output of 50 mW is a milestone for mobile
laser projection technology. Courtesy of Osram Opto Semiconductors.
The release also stated that, compared with semiconductor lasers
that operate with frequency doubling based on current technology, direct emitting
green lasers are more compact and easier to control, offer greater temperature stability
and have higher modulation capability. The main advantages of a direct-emitting
InGaN laser are a smaller form factor (similar to blue laser diodes), high modulation
capabilities and long-term price potential (similar to the blue laser), it said.
Osram noted that the main challenges lie in the fact that the
direct green laser must be competitive with its second-harmonic green laser. For
example, mobile laser projection systems need single-mode operation, 50 mW of output
power at 515 to 525 nm (this requires low threshold and good slope efficiency),
comparable wall plug efficiency and sufficiently long lifetimes.
In a report titled Progress of blue and green InGaN laser diodes
by Stephan Lutgen et al in the Proceedings of SPIE, Vol. 7616, Feb. 8, 2010, laser
operation at 516 nm with more than 50 mW of output power in CW operation is described
in combination with a wall plug efficiency of 2.7 percent.
In another report, True green InGaN laser diodes by Lutgen et
al, published in physica status solidi (a) online in May 2010, research is presented
on true-green InGaN ridge waveguide laser diodes at 520 nm on c-plane GaN substrates
in pulse operation at room temperature.
Using an LED light source, it is necessary to refocus the projector
each time the distance between the projector and screen changes. With laser light
sources, refocusing is unnecessary, regardless of the distance. The Yole report
indicated that, in 2009, the first LED-based picoprojectors were available commercially,
but, perhaps because of their poor brightness and relatively high price, no more
than 300,000 units were sold. However, LEDs and high-brightness LEDs are serious
competitors to laser-based systems because some picoprojectors have already been
announced with brightness up to 30 lm, Yole said.
Yole predicts that 10 to 20 percent of stand-alone projectors
will be laser-based by 2011, and that the ratio could grow to 50 to 75 percent by
2016. It forecasts that laser-based projection systems gradually will enter the
cell phone market, especially if direct-emission green lasers contribute to the
small size requirement. LED technology is expected to dominate until at least 2016,
A boom in media players equipped with projection functionality
is expected by 2012. Second-harmonic-generation green lasers are likely to dominate
in this market initially while waiting for direct-emission technology to become
compatible in price and performance, Yole said.