Color image reproducer having red phosphor combined with red-pass filter element

Claim 1

A TRI-COLOR CATHODE-RAY TUBE FOR PRODUCING AN IMAGE IN SIMULATED NATURAL COLOR COMPRISING: MEANS FOR PRODUCING AND PROJECTING CATHODE-RAY ELECTRONS; AND AN IMAGE SCREEN DISPOSED TO BE IMPINGED UPON BY SAID ELECTRONS AND FORMED OF THREE RELATED AND INTERLACED PATTERNS OF COLOR TARGET ELEMENTS EACH OF WHICH EMITS LIGHT OF A RESPECTIVE ONE OF RED, BLUE AND GREEN COLORS IN RESPONSE TO ENERGIZATION BY SAID ELECTRONS, THOSE OF SAID TARGET ELEMENTS WHICH EMIT SAID RED COLOR INCLUDING A PHOSPHOR COMPOSITION WHICH CONSISTS ESSENTIALLY OF A PHOSPHOR MATERIAL HAVING A DESIRED RADIATION IN RESPONSE TO ENERGIZATION BY SAID ELECTRONS IN THE RED PORTION OF THE VISIBLE SPECTRUM WITHIN THE RANGE OF 6000 TO 7000 ANGSTROMS WITH A PEAK OUTPUT OCCURRING AT APPROXIMATELY 6300 ANGSTROMS AND FURTHER HAVING AN UNDESIRED RADIATION EXTENDING FROM APPROXIMATELY 6000 ANGSTROMS INTO THE SHORTER WAVELENGTH REGION, SAID RED-COLOR TARGET ELEMENTS FURTHER INCLUDING A FILTER MATERIAL WHICH IS ABSORPTIVE OF RADIATIONS HAVING A WAVELENGTH EXTENDING FROM APPROXIMATELY 6000 ANGSTROMS INTO SAID SHORTER WAVELENGTH REGION, WHICH IS HIGHLY TRANSMISSIVE OF RADIATIONS WITHIN THE RANGE FROM 6000 TO 7000 ANGSTROMS, AND WHICH HAS A LOW REFLECTANCE AT WAVELENGTHS OF LIGHT CORRESPONDING TO THE RADIATION FROM THOSE OF SAID TARGET ELEMENTS WHICH EMIT SAID BLUE AND GREEN COLORS TO ENHANCE THE IMAGE CONTRAST-AMBIENT LIGHT CHARACTERISTIC OF SAID IMAGE SCREEN.