technical - sample and hold effect / motion blur

[madshi]

Hi guys,

I'm wondering how these digital projectors work technically. I mean film projectors in cinema show a frame, then have a black period, then show another frame, then have a black period. I believe each frame is shown twice or three times to remove the flickering.

How are digital projectors working? If you feed them a white screen for a full second, do digital projectors throw white all the time without ever showing black frames in between? Or do digital projectors shutter frames just like film projectors do, too?

I'm asking because if there are no black frames in between, we should have the sample-and-hold effect with digital projection, which would result in noticable motion blur. However, I've rarely ever seen anyone complaining about motion blur with digital projection. So my conclusion would be that digital projectors must obviously show black frames in between. But then I've never seen that being mentioned anywhere, either.

Thanks!