From Apple to OSRAM; From Displays to Devices: a Pre-CES Year-End Review of Smart Glasses From Apple to OSRAM; From Displays to Devices: a Pre-CES Year-End Review of Smart Glasses

by Christopher Grayson

Entering the fray this year have been laser-to-waveguide hybrids: using a pico-laser to illuminate the input coupling of a waveguide. These new hybrid displays—introduced in the past year by both DigiLens, and Creative Microsystems—have received a lot of attention, given their incorporation into Microsoft’s long awaited HoloLens 2 (with display developed in partnership with MicroVision).
The principal advantage to these new pico-laser driven waveguide designs is that they’ve been shown to produce a wider FOV (Field of View) than possible with existing MicroLED or LCD light-engine modules.
How they achieve a wider FOV however, is slightly different in each case. From Microsoft/MicroVision, to DigiLens, to Creative Microsystem, they’re all doing something a little different to achieve a wider field of view, but they’re all achieving it by illuminating their waveguide with a pico-laser rather than a panel based light-engine such as a MicroLED. This is interesting as the whole industry was leaning towards MicroLED for the future direction in waveguide based smartglasses’ light engines… then suddenly!
While everyone is doing something different, ultimately it comes down to pixel size. A high quality MicroLED can be manufactured that produces a point of light of about 5 μm (μm = micrometer or micron = one millionth of a meter). That sounds tiny (and it is), however a pico-laser can produce a point of light of about 0.5 μm (one-half of one millionth of a meter, or about 1/10 the size of the smallest mass producible MicroLED). Microsoft, and their partner MicroVision have been first to market with a laser light engine to waveguide hybrid display. Some have suggested this is over-engineered—it is a stupendous feat of optical engineering—Microsoft has shown that it can be done, and mass produced. Most of what is publicly known about HoloLens’ display comes from a talk given by Alex Kipman, two months ago at ETH Zurich. I had previously reported Microsoft partnering with MicroVision (through a contract, a license, and a source), but with no official acknowledgment from Microsoft or MicroVision, many saw further confirmation in one of Kipman’s ETH slides. 

h/t gaporter