Apparatus for improving visuality of projected images

Claim 1

APPARATUS FOR IMPROVING THE VISUALITY OF AN IMAGE PROJECTED ON A SCREEN COMPRISING: A BLACK BORDER SURROUNDING SAID SCREEN AND ABUTTING THE PERIPHERAL EDGES THEREOF, A REFLECTIVE AREA SURROUNDING SAID BLACK BORDER AND ABUTTING THE OUTER PERIPHERAL EDGES THEREOF, MEANS HAVING A PRIMARY LIGHT SOURCE FOR FORMING A PRIMARY BEAM OF LIGHT, MEANS FOR LOCATING AN IMAGE IN THE PATH OF SAID PRIMARY BEAM OF LIGHT, MEANS ADAPTED TO PROJECT SAID IMAGE ONTO SAID SCREEN, MEANS FOR LOCATING A MIRROR ASSEMBLY IN THE PATH OF SAID IMAGE PROJECTION PRIMARY BEAM OF LIGHT, SAID MIRROR ASSEMBLY HAVING A LIGHT TRANSMITTING CENTER PORTION ADAPTED TO TRANSMIT SUBSTANTIALLY ALL OF SAID PRIMARY BEAM OF LIGHT AND HAVING AN OPAQUE LIGHT REFLECTIVE OUTER BORDER OF HIGHLY REFLECTIVE MATERIAL, SAID MIRROR ASSEMBLY LYING IN A PLANE FORMING AN ACUTE ANGLE WITH SAID SCREEN, A SECONDARY LIGHT SOURCE OF VARIABLE LIGHT OUTPUT INTENSITY FOR FORMING A SECONDARY BEAM OF LIGHT, AN OPTICAL SYSTEM INTERCEPTING SAID SECONDARY LIGHT BEAM, POSITIONED TO DIRECT SAID SECONDARY BEAM OF LIGHT INCIDENT TO SAID REFLECTIVE OUTER BORDER OF SAID MIRROR ASSEMBLY, SAID DIRECTED SECONDARY LIGHT BEAM BEING POSITIONED WITH RESPECT TO SAID REFLECTIVE OUTER BORDER OF SAID MIRROR ASSEMBLY SO THAT SAID SECONDARY LIGHT BEAM IS REFLECTED FROM SAID REFLECTIVE BORDER ONTO SAID AREA SURROUNDING SAID BLACK BORDER FOR ILLUMINATION THEREOF, MEANS MEASURING THE INTENSITY OF SAID IMAGE PROJECTION PRIMARY LIGHT BEAM AND PRODUCING OUTPUT SIGNALS IN PROPORTION THERETO, AND MEANS COUPLED TO SAID LAST MENTIONED MEANS FOR VARYING THE LIGHT INTENSITY OF SAID SECONDARY LIGHT SOURCE IN RESPONSE TO SAID OUTPUT SIGNALS THEREFROM FOR MAINTAINING A SUBSTANTIALLY CONSTANT RELATIONSHIP BETWEEN THE INTENSITIES OF SAID PRIMARY AND SECONDARY LIGHT BEAMS, SO THAT THE LUMINANCE OF SAID ILLUMINATED AREA IS APPROXIMATELY EQUAL TO THE LUMINANCE OF SAID IMAGE PROJECTED ONTO SAID SCREEN.