US SF film (maybe 80's). A guy starts work with a company in a new town. (Maybe he moves his family there.) He is working on a device that you look through and it will tell you if the object is non-human.
I forget the details, but in the end scenario, he points the device at his boss (I think) who looks like a (very attractive) woman but the device registers her as non-human. It's one of those "aliens among us" films, but I would sure like to know the title.