Smartphone case with rear-facing viewfinder display

A protective case for a smartphone comprising:

• a housing adapted to encase the smartphone, the smartphone having at least one rear-facing camera and a Universal Serial Bus (USB) Type-C port that configured for DisplayPort Alternate Mode;
• a secondary display fixed within a recessed pocket on an exterior rear face of the housing adjacent to a camera opening of the housing;
• and an electronics sub-assembly disposed within the housing and operatively coupled between the USB Type-C port and the secondary display to convey live video from the rear-facing camera to the secondary display as a real-time viewfinder;
• the electronics sub-assembly including a protocol bridge that converts DisplayPort Alternate Mode video from the smartphone to Mobile Industry Processor Interface-Display Serial Interface (MIPI-DSI) signaling for the secondary display;
• wherein the electronics sub-assembly is dimensionally and electrically standardized for use across a plurality of smartphone-specific housings, and each of the smartphone-specific housings shares identical internal mounting interfaces that receive the electronics sub-assembly while differing only in external geometry to accommodate respective smartphone models;
• and wherein the housing lacks any second body or rotatable cover that carries the secondary display and is rotatably coupled to the housing.