Metal halide lamp for curing adhesives

Abstract

An arc lamp assembly which includes in combination a reflector and a light source which is surrounded by said reflector. A dichroic coating on the reflector functions to reflect radiation in the range of about 300 to 600 nm. The light source is an arc lamp which contains a metal halide fill component which includes a mixture of scandium iodide, or other suitable lanthanide, indium iodide and cesium iodide, whereby the lamp assembly emits effective amounts of UV radiation to cure selected chemical compositions. The fill mixture, which contains no sodium component, contributes to improved lamp life and a reduction in passive lamp failure over halide fill mixtures which contain sodium iodide as a fill component.

1. An arc lamp assembly which includes in combination a reflector and a light source which is surrounded by said reflector, the improvement comprising a dichroic coating on said reflector which functions to reflect radiation in the range of about 300 to 600 nm, and where said light source is an arc lamp which consists of contains a metal halide fill component which includes consists of a mixture of scandium iodide, indium iodide, and cesium iodide, whereby said lamp assembly emits effective amounts of UV radiation to cure selected chemical compositions, and where said metal halide mixture has the following concentrations amounts of metal halides: 
       
         
           
                 
                 
                 
               
                     
                 
                     
                     
                   ConcentrationAmount 
                 
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   ScI 3   
                   19-26  
                   μg 
                 
                     
                   InI 
                   10-53  
                   μg 
                 
                     
                   CsI 
                   185-211  
                   μg 
                 
                     
                   Total 
                   240-264  
                   μg. 
                 
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
               
            
           
         
       
     
     
       2. A miniature lamp which provides an effective source of UV radiation for curing chemical compositions which includes a reflector which surrounds a light source wherein
 (a) said reflector contains a dichroic coating selected to reflect UV radiation in the range of about 300 to 600 nm; and 
 (b) said light source including includes an elongated fused quartz envelope having a pair of opposite neck portions each with a coaxial central opening having a reduced section and a central hermetically scaled chamber containing a fill consisting of;: 
 an argon pressure at room temperature at a range of about 0.5 atmospheres to about 2.0 atmospheres; mercury in an amount in the range of about 5 mg to about 15 mg; and a mixture of metal halide material in an amount from about 50 up to 1000 micrograms wherein said metal halide mixture consists of a mixture of scandium iodide, indium iodide and cesium iodide; a pair of axially aligned electrodes respectively positioned at said opposite neck portions and separated from each other by a predetermined distance from about 0.8 to 1.5 mm, said electrodes each having a shank portion which includes a distal end, with at least one of said ends having a coil wrapped around said end. 
 
     
     
       3. The lamp of  claim 2  in which the metal halide mixture consists of the following: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                   ConcentrationAmount 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   ScI 3   
                   19-26 
                   μg 
                 
                     
                   InI 
                   10-53 
                   μg 
                 
                     
                   CsI 
                   185-211 
                   μg 
                 
                     
                   Total 
                   240-264 
                   μg. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
               
            
           
         
       
     
     
       4. The lamp of  claim 2  in which the dichroic coating is a material selected from the group consisting of silicon dioxide, aluminum oxide, zirconium dioxide, and tantalum oxide in a plurality of alternating layers of different oxides. 
     
     
       5. An arc lamp assembly which includes in combination a reflector and a light source which is surrounded by said reflector, the improvement comprising a dichroic coating on said reflector, and where said light source comprises a metal halide fill component which consists of a mixture of scandium iodide, indium iodide, and cesium iodide, whereby said lamp assembly emits ultraviolet radiation, and where said metal halide mixture has the following amounts of metal halides: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                   Amount 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   ScI 3   
                   19-26  
                   μg 
                 
                     
                   InI 
                   10-53 
                   μg 
                 
                     
                   CsI 
                   185-211 
                   μg 
                 
                     
                   Total 
                   240-264 
                   μg. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
               
            
           
         
       
     
     
       6. The arc lamp assembly of claim 5 wherein said dichroic coating is selected to reflect at least radiation in the range of about 200 to about 950 nm. 
     
     
       7. The arc lamp assembly of claim 5 wherein the volume-power loading of said lamp is about 0.8 watts/mm 3 . 
     
     
       8. A miniature lamp which includes a reflector that surrounds a light source wherein
 (a) said reflector is coated with at least one dichroic coating selected to reflect at least ultraviolet radiation; and   (b) said light source includes an elongated refractory material envelope having a pair of opposite neck portions each with a coaxial central opening and a central hermetically sealed chamber containing a fill consisting of:   an inert gas pressure at room temperature at a range of about 0.5 atmospheres to about 2.0 atmospheres; mercury in an amount in the range of about 5 mg to about 15 mg; and a mixture of metal halide material in an amount from about 50 up to 1000 micrograms wherein said metal halide mixture consists of a mixture of scandium iodide, indium iodide and cesium iodide; a pair of axially aligned electrodes respectively positioned at said opposite neck portions and separated from each other by a predetermined distance.   
     
     
       9. The lamp of claim 8 in which the metal halide mixture consists of the following: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                   Amount 
                 
                     
                     
                 
                     
                 
                 
                 
                 
                 
               
                     
                   ScI 3   
                   19-26  
                   μg 
                 
                     
                   InI 
                   10-53 
                   μg 
                 
                     
                   CsI 
                   185-211 
                   μg 
                 
                     
                   Total  
                   240-264 
                   μg. 
                 
                     
                     
                 
             
                
                
                
               
               
                
               
            
             
                
                
                
                
                
               
            
           
         
       
     
     
       10. The lamp of claim 8 in which said at least one dichroic coating comprises a material selected from the group consisting of silicon dioxide, aluminum oxide, zirconium dioxide, and tantalum oxide, said at least one dichroic coating being laid out in a plurality of alternating layers of different oxides. 
     
     
       11. The lamp of claim 8 wherein said at least one dichroic coating is selected to reflect at least radiation in the range of about 200 to about 950 nm. 
     
     
       12. The lamp of claim 8 wherein said electrodes each has a shank portion which includes a distal end, at least one of said distal ends having a coil wrapped around said end. 
     
     
       13. The lamp of claim 8 wherein said hermetically sealed chamber contains one or more inert gases selected from the group consisting of Ne, Ar, Kr, and Xe. 
     
     
       14. The lamp of claim 8 wherein the volume-power loading of said lamp is about 0.8 watts/mm 3 .