True green laser module tailored for smartphone pico-projectors
Two summers ago there was a flurry of announcements about the development of efficient, true-green lasers by R&D labs at Osram and Sumitomo Electric. Those lab results are making their way out into commercial production: Finnish start-up EpiCrystals Inc. has announced what it claims is “the smallest and most efficient green light source for pico projectors.” [UPDATE: As reader Jason points out below, the two lab announcements were for lasers that directly emit green light. The EpiCrystals device uses frequency doubling.] EpiCrystal’s game plan is that RGB (red, green, blue) laser technology will revolutionize smartphones, enabling them to project photos, video presentations and movies on almost any surface with HD-level quality and resolution. The green laser module will be available in Q1, 2012 for $45.00 in 10K volumes.
I asked EpiCrystal Vice President of Business Development Tomi Jouhti for some more information on the module and he sent these details:
• Laser has two main components: GaAs-based 1064nm IR laser chip and a PPLN waveguide type nonlinear crystal
• Laser chip has an integrated 45-degree folding mirror and lens (both are made at wafer level) for efficient coupling
• Bright true green color (532nm)**
• Laser operates in passively Q-switched mode (very simple construction, three-contact laser)
• Wide band QPM (quasi phase matching) in the crystal
• Wide band SBG (surface Bragg grating) in the crystal
• SBG locks the central frequency of the IR laser
• Spectrum width 0.5-1.0nm –> reduced speckle
• 60+ mW optical output power
• 100+ MHz modulation speed
• TO56 module, volume ~0.2cc
• Compatible with MEMS, LCoS and DLP
**[My note: “True green” light is defined by the spectral range of 515 to 535 nm.]
Erin commented:
Companies will be selling entire pico projector modules for $25 wholesale. How does a $45 laser have any chance to be competitive in that market? Not to mention that lasers require "de-speckling" which kills their efficiency. So at more cost and less efficiency, why does anyone care about laser illumination? And to comment on another comment, a 10,000 lumen tabletop projector, using lasers the way Microvision does, would burn the screen and your eyes! That's simply never going to happen. Stick with LEDs, IMO.
Meredith Poor commented:
My interest in pico projectors is to display a grid in front of a robot. If the surface is flat, the grid makes a uniform trapezoid. If there's an irregularity, it's easy to characterize. If the surface is colored differently in various areas, the projector scans through various primary colors to help identify the pattern or design. Such features would make positioning more accurate.
Jason commented:
"Those lab results are making their way out into commercial production." Not quite. Those two announcements were for "native" green lasers that directly emit green light. This EpiCrystals device uses frequency doubling with an IR laser.
parity commented:
Amen! However, is there an MT NBS standard?
I was an early "doubter" of the pico-projector hype b/c of the X3 laser power drain on a portable system. Then again, don't forget heat dissipation either. Tabletop projectors in an air conditioned office makes sense unless the lasers suddenly drop to 3mA or less.
Eric B commented:
Microvision already has a 3 laser based unit that runs up to two hours on a battery. The unit currently uses a synthetic green laser but DGLs are soon entering the market and promise lower energy consumption and smaller size. Biggest limitation currently is lumen output, requiring darkened spaces to work well. Advantage of laser based projection is that there is no need to focus the unit, no matter how much you move it it is always in focus.
Moe commented:
I thought Corning was also working on Green Laser.
Andy T commented:
The size of battery needed to run a three laser based projector for a one hour meeting (let alone the three or four hours of meetings a lot of organizations have per day, or a salesperson doing several calls each day) outweighs the packaging benefit of integrating a picoprojector. "Nice sales presentation Henrietta - too bad you can't call your boss afterwards to get her to approve the quote". Once you need to plug it in for power, you might as well dock your smartphone to a real projector and not compromise the imaging performance with mouse-testicle sized optics. Docking is where we need a smartphone STANDARD physical and electrical interface.
this is dud technology that's been looking for a inappropriate market for years, IMO.
Now, replacing a discharge lamp with one of these for an 10,000 lumen tabletop projector (with the standard docking interface) - absolutely!
