Apparatus for improving radio frequency signal transmission through low-emissivity coated glass

Abstract

A method and apparatus for modifying low emissivity (low-E) coated glass, so that windows using the processed glass allow uninterrupted use of RF devices within commercial or residential buildings. Glass processed in the manner described herein will not significantly diminish the energy conserving properties of the low-E coated glass. This method and apparatus disrupts the conductivity of the coating in small regions. In an embodiment, the method and apparatus ablates the low-E coating along narrow contiguous paths, such that electrical conductivity can no longer occur across the paths. The paths may take the form of intersecting curves and/or lines, so that the remaining coating consists of electrically isolated areas. The method and apparatus are applicable both to treating glass panels at the factory as well as treating windows in-situ after installation.

What is claimed is: 
     
         1 . An apparatus for modifying a low emissivity (low-E) coating on a sheet of glass, the apparatus comprising:
 a laser,   a lens array configured to focus said laser on locations on the low-E coating; and   two or more motors of which at least one motor is configured to control the position and movement of the laser in a first direction essentially parallel to the glass, and at least one other motor is configured to control the position and movement of the laser in a second direction that is orthogonal to the first direction and essentially parallel to the glass, wherein said two or more motors are configured to move said laser in such a manner as to ablate intersecting lines or curves in the low-E coating, creating electrically isolated areas of remaining low-E coating,   wherein said laser is configured to ablate the low-E coating at the locations along which said laser is directed as said laser is moved.   
     
     
         2 . The apparatus of  claim 1 , further comprising:
 a programmable processor configured to create and send control signals to the two or more motors wherein said control signals control the speed and direction of said motors.   
     
     
         3 . The apparatus of  claim 1 , wherein said lens array is oriented to direct said laser such that the angle of incidence of said laser is not normal with respect to the sheet of glass. 
     
     
         4 . The apparatus of  claim 1 , wherein said laser is pulsed. 
     
     
         5 . The apparatus of  claim 4 , wherein the width of each pulse is less than or equal to 100 nanoseconds (ns) and wherein said laser is configured such that each pulse delivers 3 microjoules or more of energy. 
     
     
         6 . The apparatus of  claim 4 , wherein said laser is configured and positioned to ablate a spot of the low-E coating measuring 10 to 200 microns in diameter. 
     
     
         7 . The apparatus of  claim 4 , wherein successive spots, which are ablated by said laser as it moves, overlap by 25% to over 90% by area. 
     
     
         8 . The apparatus of  claim 1 , wherein said laser is configured to operate at a wavelength greater than or equal to 1400 nm. 
     
     
         9 . The apparatus of  claim 1 , wherein said laser is configured to operate at a wavelength of approximately 1064 nm. 
     
     
         10 . The apparatus of  claim 1 , wherein said two or more motors are configured to move said laser at a velocity of approximately 1 meter per second. 
     
     
         11 . The apparatus of  claim 1 , further comprising a first rail, wherein said laser is movably mounted on said first rail, such that one or more of said two or more motors are configured to move said laser along said first rail in the first direction. 
     
     
         12 . The apparatus of  claim 11 , further comprising a second and third rail, such that a first end of the first rail is movably mounted to the second rail, and a second end of the first rail is movably mounted to the third rail,
 wherein the second and third rails are essentially parallel to each other and   wherein one or more additional motors of said two or more motors are configured to move the first end of the first rail along said second rail in the second direction and simultaneously move the second end of the first rail along said third rail in the second direction.   
     
     
         13 . The apparatus of  claim 12 , wherein said first rail comprises a first belt mounted on a first pulley at the first end of the first rail, and on a second pulley mounted at the second end of the first rail,
 wherein said one or more motors are configured to drive the first belt around said first and second pulleys, and   wherein said laser is mounted on said first belt so that driving the first belt causes the laser to move along the first rail.   
     
     
         14 . The apparatus of  claim 13 , wherein the second rail comprises a second belt mounted on a third pulley at a first end of said second rail, and on a fourth pulley at a second end of said second rail,
 wherein the third rail comprises a third belt mounted on a fifth pulley at a first end of said third rail and on a sixth pulley at a second end of said third rail,   wherein said one or more additional motors are configured to drive said second and third belts simultaneously in the second direction,   wherein the first end of the first rail is mounted on the second belt and the second end of the first rail is mounted on the third belt, and   wherein driving of the second and third belts in the second direction causes said first rail and said laser mounted thereto to move in the second direction.