Total internal reflection projection system

Claim 1

A LIGHT PROJECTION SYSTEM COMPRISING: (A) A LIGHT PERMEABLE SOLID PRISM MEANS HAVING AN ENTRANCE SURFACE, AN EXIT SURFACE AND A FURTHER SURFACE INTEGRALLY DISPOSED WITH RESPECT TO SAID ENTRANCE AND EXIT SURFACES, (B) A LIGHT MODULATING CONTROL MEDIUM OVERLAYING SAID FURTHER SURFACE AND FORMING A BOUNDARY WITH A SECOND MEDIUM, SAID PRISM MEANS AND SAID CONTROL MEDIUM HAVING APPROXIMATELY EQUAL INDEXES OF REFRACTION, SAID SECOND MEDIUM HAVING A RELATIVELY LOW INDEX OF REFRACTION, SAID BOUNDARY BEING NRORMALLY ORIENTED WITH RESPECT TO THE CRITICAL ANGLE FOR TOTAL INTERNAL REFLECTION SO AS TO EFFECT TOTAL INTERNAL REFLECTION FOR LIGHT RAYS INCIDENT THEREON FROM THE ENTRANCE SURFACE, (C) MEANS FOR DIRECTING LIGHT THROUGH THE ENTRANCE SURFACE OF SAID PRISM AT SAID BOUNDARY, THE LIGHT REFLECTED AT SAID BOUNDARY BEING MODULATED IN ACCORDANCE WITH THE MODULATION CHARACTERISTICS OF SAID CONTROL MEDIUM, THE INTERNALLY REFLECTED LIGHT EXITING FROM SAID EXIT SURFACE, AND (D) MEANS FOR PROJECTING THE INTERNALLY REFLECTED LIGHT RECEIVED FROM SAID EXIT SURFACE UPON A DISPLAY AREA.