Illuminated panel

Claim 1

IN A LUMINOUS DISPLAY BOARD, IN COMBINATION, A SIGN CARRIER OF TRANSPARENT PLATE MATERIAL HAVING A FRONTAL AND A REARWARD MAJOR FACE, SAID FACES BEING AT LEAST PARTLY EXPOSED TO AMBIENT AIR, AND AN EDGE FACE CONNECTING SAID MAJOR FACES, AT LEAST ONE OF SAID MAJOR FACES BEING SMOOTH; A SOURCE OF LIGHT ARRANGED TO TRANSMIT LIGHT TO SAID EDGE FACE FOR PASSAGE THERETHROUGH INTO SAID SIGN CARRIER AND FOR SUBSTANTIALLY TOTAL INTERNAL REFLECTION FROM SAID SMOOTH FACE WHEN THE SAME IS IN CONTACT WITH AIR; AND A SIGN LAYER OF PREDETERMINED SHAPE REMOVABLY SECURED IN CONTACT WITH A PORTION OF SAID SMOOTH FACE SO AS TO ALTER THE INTERNAL RELECTIVE PROPERTIES OF SAID PORTION AND TO TRANSMIT LIGHT FALLING THEREON FROM SAID EDGE FACE OUTWARD THROUGH SAID FRONTAL MAJOR FACE; A BACKGROUND CARRIER OF OPAQUE, YIELDABLY RESILIENT SHEET MATERIAL HAVING TWO OPPOSITE CONTINUOUS EXPOSED FACE PORTIONS, ONE OF SAID FACE PORTIONS BEING ARRANGED OPPOSITE SAID REARWARD MAJOR FACE AND OPTICALLY SHIELDING A SPACE THEREFROM; A PLURALITY OF SIGN RODS OF LIGHT TRANSMITTING MATERIAL REMOVABLY INSERTED IN SAID BACKGROUND CARRIER AND PASSING THERETHROUGH FROM ONE TO THE OTHER OF SAID FACE PORTIONS, SAID OPAQUE MATERIAL BEING ADAPTED RESILIENTLY TO CLOSE THE PASSAGES FORMED THEREIN BY INSERTION OF SAID RODS WHEN THE SAME ARE REMOVED; AND A LIGHT SOURCE IN SAID SPACE FOR TRANSMITTING LIGHT FROM SAID SPACE THROUGH SAID RODS AND SAID SIGN CARRIER SO AS TO EMANATE FROM SAID FRONTAL FACE THEREOF.