Laminated glass windscreen intended to be used at the same time as a HUD system reflector

Abstract

A laminated safety glass windscreen, which can also be used as a reflector in a HUD system, comprises at least first and second panes and a thermoplastic intermediate layer which joins these panes together. The cross-section of the intermediate layer is in the shape of a wedge, decreasing in thickness from top to bottom. The thermoplastic intermediate layer may be composed of two sheets, one of which is provided with a colored filtering strip and has a wedged cross-section conditioned by the appearance of this filtering strip. The other sheet has a wedged cross-section such that the two sheets together have the prescribed convergence angle for using the windscreen as a reflector.

1 . A laminated glass windscreen having a taper angle for a reflector in a HUD system, comprising: 
 (i) a first pane,    (ii) a second pane, and    (iii) a intermediate layer having a wedge-shaped cross-section, between said first and second panes, comprising 
 (a) a first thermoplastic sheet comprising a tinted filtering strip at an upper edge of said first thermoplastic sheet, and  
 (b) a second thermoplastic sheet, on said first thermoplastic sheet, wherein said second thermoplastic sheet has a wedge-shaped cross-section;  
   wherein 
 said first thermoplastic sheet has a taper angle k 1 , and  
 said second thermoplastic sheet has a taper angle k 2 , wherein the taper angle of said combined sheets (k 1 +k 2 ) is 0.5 mrad, and wherein at least one of either the first thermoplastic sheet or the second thermoplastic sheet has a wedge-shaped cross-section.  
   
     
     
         2 . The laminated glass windscreen of  claim 1 , wherein said first thermoplastic sheet has a taper angle of 0.  
     
     
         3 . The laminated glass windscreen of  claim 1 , wherein said first thermoplastic sheet has a wedge-shaped cross-section.  
     
     
         4 . The laminated glass windscreen of  claim 1 , wherein said intermediate layer further comprises a support sheet comprising a functional layer, between said first thermoplastic sheet and said second thermoplastic sheet.  
     
     
         5 . The laminated glass windscreen of  claim 1 , wherein said first thermoplastic sheet comprises a polymer selected from the group consisting of polyvinyl butyral and polyurethane.  
     
     
         6 . The laminated glass windscreen of  claim 1 , wherein said second thermoplastic sheet comprises a polymer selected from the group consisting of polyvinyl butyral and polyurethane.  
     
     
         7 . The laminated glass windscreen of  claim 5 , wherein said second thermoplastic sheet comprises a polymer selected from the group consisting of polyvinyl butyral and polyurethane.  
     
     
         8 . The laminated glass windscreen of  claim 1 , wherein said first thermoplastic sheet comprises polyvinyl butyral, and said second thermoplastic sheet comprises polyvinyl butyral.  
     
     
         9 . The laminated glass windscreen of  claim 4 , wherein said support sheet comprises polyethylene terephthalate.  
     
     
         10 . A method of making the laminated glass windscreen of  claim 1 , comprising: 
 laminating said first pane, said intermediate layer and said second pane.    
     
     
         11 . The method of  claim 10 , further comprising, prior to said laminating, stretching to form said first thermoplastic sheet with a wedge-shaped cross-section.  
     
     
         12 . The method of  claim 10 , further comprising, prior to said laminating, extruding to form said second thermoplastic sheet in a wedge shape.  
     
     
         13 . The method of  claim 11 , further comprising, prior to said laminating, extruding to form said second thermoplastic sheet in a wedge shape.  
     
     
         14 . The method of  claim 10 , further comprising, prior to said laminating, stretching to form said second thermoplastic sheet with a wedge-shaped cross-section.  
     
     
         15 . The method of  claim 11 , further comprising, prior to said laminating, stretching to form said second thermoplastic sheet with a wedge-shaped cross-section.  
     
     
         16 . A method of making the laminated glass windscreen of  claim 4 , comprising: 
 laminating said first pane, said intermediate layer and said second pane.    
     
     
         17 . A method of displaying an image, comprising: 
 projecting an image on the laminated glass windscreen of  claim 1 .    
     
     
         18 . A method of displaying an image, comprising: projecting an image on the laminated glass windscreen of  claim 4 .  
     
     
         19 . A vehicle, including the laminated glass windscreen of  claim 1 .  
     
     
         20 . A method of displaying an image, comprising: 
 projecting an image on a windscreen of a vehicle, wherein said windscreen is the laminated glass windscreen of  claim 1 , and    reflections of said image from said first pane and said second pane appear superimposed to a driver of said vehicle.    
     
     
         21 . The laminated glass windscreen of  claim 1 , wherein said second thermoplastic sheet (b) is untinted.  
     
     
         22 . The laminated glass windscreen of  claim 1 , wherein k 1  is 0.185 mrad and k 2  is 0.315 mrad.