US Patent 11247421 Single-step extrusion of fiber optic plates for electronic devices

An electronic device may have a housing with a display. A protective display cover layer for the display may have an image transport layer such as a fiber optic plate. The fiber optic plate may be formed from fibers. An extruder may form fiber bundles that each include a respective plurality of fibers distributed in binder material. The fiber bundles from the extruder may be fed directly to a block forming die. The block forming die may receive the fiber bundles from the extruder and output a unitary fiber block. The fiber bundles may remain heated in the block forming die such that the binder material of the fiber bundles seamlessly merges during formation of the unitary fiber block. A cutter can be used to cut off a layer of the unitary fiber block. This layer may be machined and polished to form the fiber optic plate.