Patent attributes
A phosphor screen for image forming including phosphor material being excitable by light in a wavelength λ1. The phosphor screen receives an optical image from an image forming optical system and produces the optical image at a second wavelength λ2. The phosphor screen includes a phosphor layer comprising the phosphor material. A short-pass reflective coating is positioned on a first side of the phosphor layer. The short-pass reflective coating transmits the wavelength λ1 and reflects the wavelength λ2. A long-pass reflective coating is positioned on a second side of the phosphor layer. The long-pass reflective coating transmits the wavelength λ2 and reflects the wavelength λ1. A first substrate is positioned over the short-pass reflective coating. The first substrate is formed of optically clear and thermal conductive material. A second substrate is positioned over the long-pass reflective coating. The second substrate is formed of long-pass absorptive optical filter material that transmits the wavelength λ2 and absorbs wavelength λ1 from ambient light to prevent the phosphor layer from being excited by the ambient light. The phosphor screen may alternatively be used for a direct-view visual display apparatus. These principles can also be utilized for backlighting and general illumination applications.
