My cat is petrified of the click when his new infra-red cat flap opens. so he wont use it?

he wont go anywhere near it he watches it carefully when he walks past it, looks like he think its going to eat him or something?? he was ok with the normall cat flap but got this to stop other cats coming in, but he wont even use it. ive tried putting him thru it with a bit of force but he struggles away and wont return to it. anyone have any idea???