Patent ID: 7733571

Claim:
A visual display apparatus, comprising: a) an excitation light source for providing light in a first wavelength λ 1 ; b) a light modulating device for receiving light from said excitation light source and modulating said light to form an image; c) an imaging forming optical system for receiving outputted light from said light modulating device and magnifying and relaying said image; and, d) a phosphor screen, comprising phosphor material being excitable by light in said first wavelength λ 1 , said phosphor screen for receiving said optical image from said image forming optical system and producing said optical image at a second wavelength λ 2 , said phosphor screen, comprising: i. a phosphor layer comprising said phosphor material emitting said second wavelength λ 2 ; ii. a short-pass reflective coating positioned on a first side of said phosphor layer, said short-pass reflective coating for transmitting said wavelength λ 1 and reflecting said wavelength λ 2 ; iii. a long-pass reflective coating positioned on a second side of said phosphor layer, said long-pass reflective coating for transmitting said wavelength λ 2 and reflecting said wavelength λ 1 ; iv. a first substrate positioned over said short-pass reflective coating, said first substrate being formed of optically clear and thermal conductive material for transmitting said wavelength λ 1 and dissipating heat generated by said phosphor layer during high intensity operation; and, v. a second substrate positioned over said long-pass reflective coating, said second substrate being formed of long-pass absorptive optical filter material that transmits said second wavelength λ 2 and absorbs said wavelength λ 1 from the ambient light for improving display contrast ratio in bright ambient conditions, wherein said first substrate comprises optically clear and thermal conductive material having a thermal conductivity in a range of 0.7 watt/(K·m) to 30 watt/(K·m).