Patent ID: 6262589
Filing Date: 2001-07-17
Classification: G01R,G09G

Abstract:
A method of TFT array inspection comprising the steps of:charging a pixel capacitance C.sub.P constituting a pixel of a TFT array with a pixel voltage V.sub.P having a known value and charging an additional capacitance C.sub.T (C.sub.T>>C.sub.P) with a set voltage V.sub.S (V.sub.P.noteq.V.sub.S) having a known value, said additional capacitance C.sub.T including at least a line capacitance C.sub.S (C.sub.S >>C.sub.P) having an unknown value and said additional capacitance C.sub.T being connected in parallel with said pixel capacitance C.sub.P during inspection of said pixel, after the charging of both of these, connecting said pixel capacitance C.sub.P and said additional capacitance C.sub.T in parallel, and measuring a difference voltage .DELTA.V.sub.S between a voltage V.sub.a of said additional capacitance C.sub.T after the parallel connection and said set voltage V.sub.S, said charging and said connecting of said pixel capacitance C.sub.P and said additional capacitance C.sub.T and said measuring being conducted at least twice, by changing a value of said additional capacitance C.sub.T with use of at least one reference capacitance .DELTA.C.sub.S having a known value, thereby measuring at least two difference voltages .DELTA.V.sub.S having difference values; andinspecting said pixel based on at least these two measured difference voltages .DELTA.V.sub.S and the following equation representing these difference voltages .DELTA.V.sub.S :.DELTA.V.sub.S =V.sub.a -V.sub.S =:(C.sub.P /C.sub.T).multidot.(V.sub.P -V.sub.S)(where =: means ""approximately equal to"").