Light-emitting diodes (LED); luminous signs; luminous safety signs; luminous beacons; luminous safety beacons; luminous signaling panels and/or indicators, namely, luminescent display panels and luminescent indicator panels for signaling; photoluminescent beacons for warning purposes; photoluminescent safety beacons; photoluminescent signaling panels and/or indicators, namely, luminescent display panels and luminescent indicator panels for signaling