Method for backside sealing organic light emitting diode (OLED) displays

Abstract

A hermetically sealed glass package and method for manufacturing the hermetically sealed glass package are described herein. In one embodiment, the hermetically sealed glass package is suitable to protect thin film devices which are sensitive to the ambient environment. Some examples of such glass packages are organic emitting light diode (OLED) displays, sensors, and other optical devices. The present invention is demonstrated using an OLED display as an example.

1 . A method for manufacturing a glass package, said method comprising the steps of: 
 providing a cover plate;    providing a substrate plate;    depositing a frit onto said cover plate;    depositing at least one thin film device onto said substrate plate; and    directing a laser beam at said cover plate so that said laser beam passes through said cover plate and heats said frit such that said frit melts and forms a hermetic seal which connects said cover plate to said substrate plate and also protects said at least one thin film device located between said cover plate and said substrate plate.    
     
     
         2 . The method of  claim 1 , wherein said frit has a height ≦50 μm.  
     
     
         3 . The method of  claim 1 , wherein said frit is glass doped with a material that is absorbent at a specific wavelength of light.  
     
     
         4 . The method of  claim 1 , wherein said frit is heated by the laser beam so that a substantially constant temperature is maintained in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         5 . The method of  claim 4 , wherein said electrodes are metal non-transparent electrodes that have different patterns and different optical properties.  
     
     
         6 . The method of  claim 4 , wherein said electrodes are reflective, absorptive, transmissive or any combination thereof.  
     
     
         7 . The method of  claim 1 , wherein said directing step further includes dynamically changing a power of the laser beam to maintain a substantially constant temperature in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         8 . The method of  claim 1 , wherein said directing step further includes dynamically changing a speed of the laser beam to maintain a substantially constant temperature in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         9 . The method of  claim 1 , further comprising the step of placing a reflector under said substrate before the laser beam is used to melt said frit so as to maintain a substantially constant temperature in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         10 . The method of  claim 1 , further comprising the step of placing a partially reflective mask on top of said cover plate before the laser beam is used to melt said frit so as to maintain a substantially constant temperature in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         11 . The method of  claim 1 , wherein said directing step further includes emitting the laser beam at a relatively low power to melt said frit along a sealing line during a first pass and then during a second pass emitting the laser beam at a relatively high power to melt said frit only at portions of said frit along the sealing line which did not reach a correct temperature during the first pass of said relatively low power laser beam.  
     
     
         12 . The method of  claim 1 , wherein said directing step further includes using a feedback mechanism to control a laser source, which emits the laser beam, in a manner such that when said frit is melted a substantially constant temperature is maintained in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         13 . The method of  claim 12 , wherein said feedback mechanism measures a hot spot intensity of said frit along the sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         14 . The method of  claim 1 , wherein said directing step further includes using a focusing lens and a specially shaped aperture to defocus and shape the laser beam such that when said frit is melted a substantially constant temperature is maintained in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         15 . The method of  claim 1 , wherein said directing step further includes using an elliptical focusing lens to shape the laser beam such that when said frit is melted a substantially constant temperature is maintained in said frit along a sealing line that has regions free of electrodes and regions occupied by electrodes which are connected to said at least one thin film device.  
     
     
         16 . The method of  claim 1 , further comprising the step of pre-sintering said frit to said cover plate.  
     
     
         17 . The method of  claim 1 , wherein each thin film device is an organic emitting light diode.