How do I deal with professors that are biased against laptop users?

Every semester, there’s at least one professor who’s had a bad experience with laptop users (or is just old enough to see them as the work of the Devil). They are always convinced that laptop users are not taking notes with their laptops, but instead surfing the internet. Today, this semester’s teacher even singled me out twice (once during class) to mention how laptop users should look up every once in a while and make eye contact so she knows we’re paying attention. Problem: I did look up – at least 50% of the time. I tried to make eye contact. Unfortunately, in a class of 50 students where I’m in the back row, that isn’t always easy – and I feel like I shouldn’t have to constantly be sorta flagging her down, going “Look! I’m paying attention”, especially when that then means I miss taking notes. Maybe I look at the computer screen more than your average computer note taker, but I NEVER surf the web except to look up a definition or wikipedia page on something just mentioned in class, nor am I doing anything else on the computer. What can I do to let these teachers know that I’m not a bad student, and make it so that they trust me and this is no longer an issue?