https://www.theverge.com/circuitbreaker/2018/6/23/17496788/vivo-nex-teardown-pop-up-camera

Chinese smartphone makers have gone down a clever new path to get rid of the display notch and create a truly edge-to-edge screen: they’re now building pop-up cameras into their phones. We’ve seen both Oppo and Vivo do it in the span of a few weeks, and the latter’s Nex smartphone has already been put through the teardown process at MyFixGuide.

In the shots, you can see all the mechanics and components that make the slide-up motion possible on the selfie camera. There’s a spring in there, but it’s actually the silver spiral stepper to the right that pushes the camera up. It all seems fairly well put together, but moving parts are moving parts and thus more prone to failure.