HoloLens 2 widened a waveguide, not the audience for its image

What you see

Microsoft introduced HoloLens 2 at Mobile World Congress in Barcelona, and its own hardware page, live within a day of the announcement, promised wearers could ‘see more holograms at once through the greatly increased field of view’ and ‘read text and see intricate details on 3D images more easily.’ As with the original device, the imagery appears only inside the two lenses of the visor. A person standing next to the wearer sees an ordinary transparent visor and nothing projected into the room; there is no external screen and no beam of light visible from outside the headset.

How it works

Microsoft’s display support page describes the second-generation optics as ‘a combination of waveguides and light projectors,’ with laser illumination and the same tech page’s spec sheet naming the optics ‘see-through holographic lenses (waveguides).’ The support documentation is explicit about what changed from the first headset: ‘technology developments allowed Microsoft to produce waveguides that doubled the field-of-view’s area and produce light projectors with a display that are up to three times brighter.’ Eye tracking and two-handed hand tracking, both listed on the hardware page as new sensing capabilities, do not alter how the image reaches the eye; they change how the wearer points at and manipulates it.

Viewing conditions and limits

Microsoft’s own documentation frames field of view, brightness and color uniformity as a fixed trade-off set by ‘the hardware,’ not a specification that can be improved in one dimension without cost elsewhere; it says continued technology advancement is needed to loosen that trade-off further. The support page also lists conditions that degrade the visible image — an uncalibrated interpupillary distance, insufficient brightness settings, or a visor held too far from the eyes — confirming the display’s quality depends on wearer-specific setup, not a fixed broadcast image. As with the original headset, only the wearer sees the result; the improvements are to a private, single-viewer display, not to any shared or bystander-visible projection.

What it is not

A wider field of view and brighter waveguides do not turn HoloLens 2 into a free-space hologram or a light-field display that multiple people could view simultaneously from different angles without a headset. Microsoft’s own generational comparison concerns two waveguide-and-projector combiners, not two different classes of optical hologram; the underlying limitation — a private, per-eye image formed by diffracting light toward one wearer’s pupils — persists across the upgrade the company itself is describing.

• Is the improvement being advertised about the optical combiner (field of view, brightness) or about sensing (hand and eye tracking)?
• Does the specification sheet state whether a figure is a device average or a peak, best-case number?
• Can more than one wearer see the identical hologram at once, or does each headset render its own private copy?

HoloLens 2’s launch materials show a company refining a waveguide headset’s field of view and brightness release over release, while the underlying mechanism — and its single-viewer limit — stayed the same as the one described at the original 2015 unveiling.