year to more than three million in 2013.
Sanju Khatri, principal analyst for sig-nage/projection at iSuppli, said tiny displays have been a major obstacle, preventing smart phones and small laptops from
becoming primary platforms for computing and Internet access.
“The growth potential for embedded
pico projectors will be limited during the
next few years due to challenges in areas
including power consumption, size and
manufacturing,” she said. “As these issues
are resolved, pico projectors will appear in
many more mobile electronics devices.”
That might make microprojectors the
hot accessory, possibly as soon as this
Christmas. The upside: You could soon
project bigger versions of the photos or
videos from mobile devices onto virtually
any surface without having to download
them first. The downside: There may be
no escaping a slide show of Uncle Phil’s
two weeks in Branson, Mo.
Self-contained pico projectors now are
about the size of a garage-door opener, but
the trend is to embed them into portable
things, such as a cell phone, an MP3
player or a digital camera.
Pico projectors with laser light sources
are expected on the market sometime this
year as consumers demand smaller devices. Diode manufacturers have been
busy building diodes that lase at shorter
and shorter wavelengths because the
shorter the wavelength, the less power
they use and the brighter the image is to
the human eye.
“We are still planning to begin initial
shipments of SHOWWX later this summer,” said Matt Nichols, director of communications for the Redmond, Wash.-based Microvision. SHOWWX is a
handheld pico projector driven by the
laser-based PicoP display engine. (For
more information on projection technology, see “Microdisplays: Coming Soon to
an Eye Near You?” September 2008, p.
68, and, in this issue, “Flat Screens Go
Deep – and More,” p. 56.)
High-power red laser diodes emitting at
660 nm are standard in devices such as
recordable DVD players, but that wavelength appears relatively dark to the
human eye, making the diodes ill-suited
for compact projectors equipped with
Mitsubishi Electric said it solved that
problem with its new red series – diodes
that emit at 638 nm – which provide the
A green laser emits from an oscillator. Courtesy of
Sumitomo Electric Industries Ltd.
brightness needed for pico projectors.
The company introduced the red diodes
at Laser World of Photonics in Munich in
June, saying they appear much brighter
than 660 nm or even the commonly used
645-nm diodes at the same output power.
Blue (450 to 480 nm) diodes showed up
about 15 years ago and are used now in
Blu-ray disc players. In January at Photonics West 2009, Osram Opto Semiconductors GmbH of Regensburg, Germany,
announced a blue laser with a wavelength
of 450 nm and an output of 50 mW that it
said is the smallest in its class.
It ain’t easy beamin’ green
One hurdle that laser makers have had
to overcome is with the green wavelength,
which stretches from 520 to 570 nm, with
532 considered optimal for displays.
Green lasers have been achieved
through frequency conversion of infrared
lasers but have been unable to directly
emit green light. Recently, engineers have
been inching closer to pure green emitters
by producing wavelengths in the blue-green spectrum.
In February, researchers at Rohm Co.
Ltd. in Kyoto, Japan, said they had pushed
a gallium nitride (GaN) diode to the
longest recorded wavelength yet produced,
499.8 nm, but said their technique is not
suitable for mass production. Later that
month, Osram Opto Semiconductors Inc.,
whose North American headquarters is in
pico projector, the SHOWWX.
Courtesy of Microvision Inc.
Sunnyvale, Calif., published a paper in
Applied Physics Letters describing an
electrically pumped 500-nm-emitting
diode based on its blue technology. In
May, in an Applied Physics Express paper,
Nichia Corp. of Tokushima, Japan, said it
had created a 515-nm device. (At press
time, Osram Opto announced it achieved a
direct-emitting green indium GaN laser at
Then in July, Sumitomo Electric Industries Ltd. of Osaka, Japan, announced that
it had created the first direct-emitting green
laser at 531 nm. The company said it overcame a problem with GaN semiconductors
(used commercially for blue LEDs), in
which the material’s luminance efficiency
rapidly declines as the wavelength increases, by developing a GaN crystal that
inhibits the efficiency drop. The result was
room-temperature pulse operation of a
laser diode emitting in the pure-green
region at 531 nm. Sumitomo has applied
for 60 patents on the technology.
Spectralus Corp. of Santa Clara, Calif.,
is reporting this month at the Eurodisplay
2009 conference on its developments in
green laser efficiency. In June, it announced a milestone in shrinking green
lasers: an eight-pin butterfly package for
its 100-mW green laser. It also said that
the lasers demonstrated 30 percent optical-to-optical (808- into 532-nm wavelength)
conversion efficiency levels.
The company said in a statement that it
is preparing a mass-production package
tailored for pico and embedded projectors
for the fourth quarter of 2009.
Microvision signed a supply deal with
Corning Inc. of Rochester, N. Y., in May
for its G-1000 synthetic green lasers and
an agreement with Osram Opto for its blue
and green lasers, to ensure an ample supply of diodes as it prepares to begin commercial production of the SHOWWX.
Nichols said he expects quantities to be
in the thousands for the remainder of this
year, constrained more by supply than by