Patent attributes
A head-mounted device may have a head-mounted housing. The head-mounted housing may have rear-facing displays that display images for a user. The images are viewable from eye boxes while the head-mounted device is being worn by the user. The displays may be mounted in left and right optical modules that have respective left and right lenses. A positioning system may be used to adjust the spacing between the left and right optical modules to accommodate different interpupillary distances. An adjustable heat extraction system may be provided that includes fans configured to force air between airflow inlets and outlets past heat sinks. The heat sinks may have fins that are adjusted in orientation and/or that are otherwise adjusted based on changes in optical module spacing. The airflow inlets and/or outlets may have adjustable louvers or other movable members that allow these ports to be fully opened, fully closed, or partly closed.