Deformable liquid crystal sensing head

Abstract

The method includes a step of contacting a surface of a sensing material to a surface of a substrate to form a mutual contact area between at least a portion of the surface of the sensing material and at least a portion of the surface of the substrate. The method also includes applying a first test signal to an electrode electrically connected to a component on the substrate. The method further includes illuminating the sensing material. The method also has a step of detecting light that has interacted with the sensing material to determine any changes induced in the sensing material by defects in the substrate manifest by applying the first test signal to the electrode. In an apparatus embodiment, a deformable sensing head is disclosed. The sensing head can be sensitive to voltage and heat changes on the substrate plate under test. In a preferred embodiment, the deformable sensing head has inflatable sensing material. The invention should have particular use in testing liquid crystal display panels.

What is claimed is:  
     
         1 . A method of testing an electrically conductive substrate, the method comprising the steps: 
 contacting a surface of a sensing material to a surface of a substrate to form a mutual contact area between at least a portion of said surface of said sensing material and at least a portion of said surface of said substrate;    applying a first test signal to an electrode on said substrate;    illuminating said sensing material; and    detecting light that has interacted with said sensing material to determine any changes induced in said sensing material by defects in said substrate manifest by said applying said first test signal to said electrode.    
     
     
         2 . A method of testing as recited in    claim 1    further comprising applying a second test signal to said sensing material to sensitize said sensing material to said defects.  
     
     
         3 . A method of testing as recited in    claim 1    wherein said contacting step includes a substep of covering entirely said surface of said substrate with said at least portion of said surface of said sensing material.  
     
     
         4 . A method of testing as recited in    claim 1    wherein said contacting step includes a substep of increasing said mutual contact area after an initial contact is made between said surface of said sensing material and said surface of said substrate.  
     
     
         5 . A method of testing as recited in    claim 1    wherein said sensing material is inflatable, the method further comprising inflating said sensing material such that said at least portion of said sensing material is in contact with said at least portion of said surface of said substrate while said sensing material is inflated.  
     
     
         6 . A method of testing as recited in    claim 1    further comprising a step of digitizing light detected in said detecting step into raw electrical signals representing said detected light  
     
     
         7 . A method of testing as recited in    claim 6    further comprising displaying said raw electrical signals on a video monitor.  
     
     
         8 . A method of testing as recited in    claim 1    wherein optical properties of said sensing material are heat sensitive whereby said detecting step determines heat changes on said substrate caused by said defects.  
     
     
         9 . A method of testing as recited in    claim 1    further comprising a step of aligning said substrate with respect to said sensing material.  
     
     
         10 . A tester for detecting defects in an electrically conductive substrate, the tester comprising: 
 a deformable sensing head having a sensing material sensitive to states of a substrate, said deformable sensing head positioned such that during testing said sensing material is in contact with, and conforms with, a portion of a surface of said substrate; and    a pattern generator electrically connected to an electrode electrically connected to a component on said substrate, said pattern generator producing an electrical test signal to activate said component via said electrode such that any defects in said electrode and said component are manifest as a state change of said substrate when said test signal is applied.    
     
     
         11 . A tester as recited in    claim 10    wherein said deformable sensing head is compressible.  
     
     
         12 . A tester as recited in    claim 11    wherein said sensing material is a crystal material.  
     
     
         13 . A tester as recited in    claim 11    wherein said deformable sensing head includes clear silicone rubber wherein said sensing material is attached to a surface of said clear silicone rubber.  
     
     
         14 . A tester as recited in    claim 10    wherein said deformable sensing head is inflatable.  
     
     
         15 . A tester as recited in    claim 14    further comprising a fluid system for inflating said deformable sensing head.  
     
     
         16 . A tester as recited in    claim 14    wherein said sensing material is a crystal material.  
     
     
         17 . A tester as recited in    claim 10    when an optical property of said sensing material is heat sensitive such that temperatures on said surface of said substrate are detected.  
     
     
         18 . A tester as recited in    claim 10    wherein an optical property of said sensing material is voltage sensitive such that voltages on said surface of said substrate are detected.  
     
     
         19 . A tester as recited in    claim 18    wherein said pattern generator is electrically connected to said sensing material and transmits a biasing signal to said sensing material to sensitize said sensing material to said defects.  
     
     
         20 . A tester as recited in    claim 10    further comprising a camera detecting light that has interacted with said sensing material thereby detecting an optical property of said sensing material which changes in response to said state change whereby said camera detects said defects.  
     
     
         21 . A tester as recited in    claim 20    wherein said pattern generator is electrically connected to said camera and transmits a switching signal to said camera to activate said camera.  
     
     
         22 . A tester as recited in    claim 20    further comprising a digitizer transforming light detected by said camera into raw electrical signals.  
     
     
         23 . A tester as recited in    claim 22    further comprising a computer which tabulates defect data from said raw electrical signals.  
     
     
         24 . A tester as recited in    claim 22    further comprising a video monitor displaying said raw electrical signals.  
     
     
         25 . A tester as recited in    claim 10    wherein said deformable sensing head and said probe lead are engaged to form an integrated probe frame such that an alignment of said probe lead to said electrode requires at a least a partial alignment of said deformable sensing head to said substrate.  
     
     
         26 . A tester as recited in    claim 10    further comprising a light source for illuminating said sensing material such that an optical property of said sensing material is detectable.  
     
     
         27 . A tester as recited in    claim 26    wherein said light source is florescent lamp.  
     
     
         28 . A tester as recited in    claim 26    wherein said light source is activated by a signal sent from said pattern generator.  
     
     
         29 . A tester as recited in    claim 26    further comprising a transparent support supporting said substrate and permitting light from said light source to illuminate said substrate.  
     
     
         30 . A deformable sensing head for use in an electrically conductive substrate tester, the deformable sensing head comprising: 
 a sensing material sensitive to changes in state of a substrate under test such that during testing said sensing material is in contact with a surface of said substrate and such that said sensing material conforms with a portion of said surface of said substrate.    
     
     
         31 . A deformable sensing head as recited in    claim 30    further comprising a probe lead engaged with said sensing material and electrically connected to an electrode on said substrate under test such that an alignment of said probe lead to said electrode requires at least a partial alignment of said deformable sensing head to said substrate under test such that said deformable sensing head and said probe lead form an integrated probe frame.  
     
     
         32 . A deformable sensing head as recited in    claim 31    further comprising a transparent structure attaching said deformable sensing head to said probe lead and permitting light to be transmitted to and received from said sensing material via said transparent structure such that optical properties of said sensing material sensitive to defects on said substrate are detectable.  
     
     
         33 . A deformable sensing head as recited in    claim 30    further comprising a clear compressible material attached to said sensing material and permitting said conforming of said sensing material with said portion of said surface of said substrate.  
     
     
         34 . A deformable sensing head as recited in    claim 33    wherein said compressible material is clear silicone rubber.  
     
     
         35 . A deformable sensing head as recited in    claim 33    wherein said sensing material is a liquid crystal material.  
     
     
         36 . A deformable sensing head as recited in    claim 30    wherein said deformable sensing head is inflatable.  
     
     
         37 . A deformable sensing head as recited in    claim 36    further comprising a fluid system for inflating said deformable sensing head.  
     
     
         38 . A deformable sensing head as recited in    claim 36    wherein said sensing material is a crystal material.  
     
     
         39 . A deformable sensing head as recited in    claim 30    wherein an optical property of said sensing material is heat sensitive such that temperatures on said surface of said substrate are detectable.  
     
     
         40 . A deformable sensing head as recited in    claim 39    wherein said sensing material is a crystal material.  
     
     
         41 . A deformable sensing head as recited in    claim 30    wherein an optical property of said sensing material is voltage sensitive such that voltages on said surface of said substrate are detectable.  
     
     
         42 . A deformable sensing head as recited in    claim 41    wherein said sensing material is a polymer dispensed liquid crystal material.  
     
     
         43 . A deformable sensing head as recited in    claim 41    wherein said sensing material is sensitized to defects in said substrate by a biasing signal.  
     
     
         44 . A deformable sensing head as recited in    claim 30    wherein said sensing material has a convex surface such that when said sensing material makes contact with said surface of said substrate an area of mutual contact and conformity between said sensing material and said surface of substrate increases as said deformable sensing head pushes upon said substrate.