Projection display device

Abstract

The invention relates to a projection display device having an illumination system comprising a light source and an optical system for providing an illumination beam. The projection display device is further provided with an image display system for modulating the illumination beam with image information and projecting an image on a screen. In order to filter ultra-violet and infra-red radiation from the light source, a filter means is present which transmit visible light. Cooling means comprising a cooling liquid are present for cooling the filter means. In the projection display device the filter means comprises the cooling liquid which contains a radiation-absorbent additive for absorbing the ultra-violet and infra-red radiation.

1 . A projection display device including an illumination system having a light source and optical system that provide an illumination beam that includes visible light and nonvisible light including at least one of infrared and ultraviolet radiation, comprising: 
 an image display system that modulates the illumination beam with image information and projects an image onto a screen, and    a filter element that absorbs the nonvisible light and transmits the visible light to the optical system,    the filter element including a liquid that contains a radiation-absorbent additive that absorbs the nonvisible light.    
     
     
         2 . The device of  claim 1 , wherein the radiation-absorbent additive is soluble in a solvent comprised by the liquid.  
     
     
         3 . The device of  claim 2 , wherein said nonvisible light includes ultraviolet radiation of wavelengths between 250 and 425 nm.  
     
     
         4 . The device of  claim 3 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of benzophenonephosphates and benzotriazolephosphates.  
     
     
         5 . The device of  claim 3 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of benzophenonesulphates and benzotriazolesulphates.  
     
     
         6 . The device of  claim 3 , wherein the solvent is organic and the radiation absorbent substance is selected from the group consisting of benzophenones and benzotriazoles.  
     
     
         7 . The device of  claim 2 , wherein said nonvisible light includes infrared radiation of wavelengths between 800 and 950 nm.  
     
     
         8 . The device of  claim 7 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of carbocyanines.  
     
     
         9 . A projection display device including an illumination system having a light source and optical system that provide an illumination beam that includes visible light and nonvisible light including at least one of infrared and ultraviolet radiation, comprising: 
 an image display system that modulates the illumination beam with image information and projects an image onto a screen, and    a filter element including a liquid that absorbs the nonvisible light and transmits the visible light to the optical system.    
     
     
         10 . The device of  claim 9 , wherein the liquid contains a radiation-absorbent substance that absorbs the nonvisible light and is soluble in a solvent comprised by the liquid.  
     
     
         11 . The device of  claim 10 , wherein said nonvisible light includes ultraviolet radiation of wavelengths between 250 and 425 nm.  
     
     
         12 . The device of  claim 11 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of benzophenonephosphates and benzotriazolephosphates.  
     
     
         13 . The device of  claim 11 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of benzophenonesulphates and benzotriazolesulphates.  
     
     
         14 . The device of  claim 11 , wherein the solvent is organic and the radiation absorbent additive is selected from the group consisting of benzophenones and benzotriazoles.  
     
     
         15 . The device of  claim 10 , wherein said nonvisible light includes infrared radiation of wavelengths between 800 and 950 nm.  
     
     
         16 . The device of  claim 15 , wherein the solvent is water and the radiation-absorbent substance is selected from the group consisting of carbocyanines.