it all depends on how much the "competition" wishes to obtain the info you display. Because if you display it on the screen, it can be copied (screen capture software or as last resort, use a camera).
It reminds me of a big company where some smart guy decided they will handle important info on special paper which cannot be copied on copy machines (you just obtain black pages).
So I just told them: don't worry, if I need the info and I want to have it, I'll just make a picture with my phone of each page.
You are more or less in the same situation. If you display it on screen, it's just a question of how much effort does it take to copy it, not if it's possible.
Considering you have a PDF document, and supposing you have no control over its source content, what I would choose to implement is the following:
1. convert each of the PDF's pages into pictures (.JPG)
2. custom PHP/JavaScript implementation where these pictures are splitted serverside into smaller pictures (i.e. 10x10 = 100 small pics of each page), each with a randomly generated name, which are then served to the Browser's JavaScript client which arranges them in order to form the screen image.
One would have to save 100 mini-pics for each page, then recompose them just like a puzzle... pretty hard unless you really want that info.
Or he could just print the screen, as I told you above. But if I would have to try to make things more difficult, this is the best solution I could come up since I read your post 10 mins ago