In The Right Conditions, Switchable Glass And Laser Projectors Have Possibilities

August 20, 2019 by Dave Haynes

I’ve seen switchable glass demo’d by NEC for rear projection window displays at a couple of trade shows this year, and while I thought it was interesting, the visual impact was a little muted. It had that age-old problem of not being bright enough to be effective in many scenarios.

Last week at NEC’s splashy new offices in Chicago, I saw a third demo, and was a lot more impressed by a set-up that pairs Avery-Dennison’s on-off glass with an NEC laser projector. The visuals had a lot more pop and NEC was showing it on an interesting corner glass window set-up, using a projector inside a meeting room that put an image on glass facing the reception area.

So why was it much better now?

Turns out that the projectors used for demos at DSE and InfoComm had short-throw lenses, to enable a view through to inside a display area, when the glass was in a clear, transparent state. At DSE, the middle of three panels had a mannequin that appeared when the glass was clear, but viewers didn’t see when the glass was switched to the opaque mode that allowed projection.

An NEC tech who was fiddling with the projection system at the Chicago office said the angle of projection used for the tradeshows educed the amount of light picked up by the switchable glass.

So at the offices, the projector is ceiling mounted at an opposite corner to the display glass, allowing a full and more direct “throw” of the visuals – and generating a lot more pop to the images.

Window projection has always had a few barriers to adoption for digital signage applications, but they’re gradually being addressed:

The uses for projection are still limited because projection won’t win battles with bright sunlight, and because of the “throw” needed to get this working well visually. But in situations with controlled lighting and room set-ups that allow a projector to be set back (like in offices and larger showrooms), this stuff is interesting.

  1. Paul Fleuranges says:

    It was kinda cool wasn’t it. I was impressed with how clear the image was as opposed to other times. I guess that stands to reason given your explanation.

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