These are called holoprojectors. They can come in a bunch of different sizes, but they’re generally all called the same thing. There are some instances of handheld holoprojectors being referred to as holopads (which comes from the term holoprojector pads). If you’re talking about, for example, the ones the clones carry, it’s your choice which term to use.
On that note, I’ve been working on a list of vocabulary which will be linked in my blog description and home page when it goes up. If you or anyone else would like to suggest stuff to include, go ahead and do it! @pomrania especially, because you gave me the idea to do it in the first place.
I hope that helps, and don’t be afraid to ask if you need more help with terminology!
~ Jacen