Ipad3 apple tv synchronisation/mirroring how can i create a full screen view on my tv ?

You'll need to use the controls on your TV. There might be a button named Wide / Zoom / Resolution/ Size or you'll have to access the TV's options/settings.

The exact options and names vary amongst TV Brands

Mirroring will of course send an image at 4:3 (the ratio of your iPad). If your TV is "Widescreen" its 16:9. So if you want to fill the screen you have to either distort the image (by stretching just the width - call "wide zoom on Sony's, "Stretch on some other brands) or enlarging the the whole thing (effectively eover-zooming which will chop off some of the top or bottom.) Again this varies according to brand.

If your TV isn't widescreen, one of the options should work fine for you. Most of the TVs I've owned have an option called "Full" which seems to work. Of course this causes enlarged or doubled pixels, so the image might not be as sharp.

Hope this helps.