The present invention provides a picture element inspecting apparatus and method
for an active matrix type display that is constituted by an LCD array device or
an EL array device, which is capable of canceling the irregularities in source
switches 13, the noise caused by device driving signals, and the irregularities
in devices in the measurement apparatus, and enhancing the accuracy of a picture
element inspection. The present invention is based on the finding that irregularities
in the direction of the source lines 8 can be canceled by performing, in
addition to a charging step and first sensing step that are realized by the charging
and discharging of picture elements 2, a second sensing step in a state
where gate lines are not selected, and subtracting correction picture element data
thus obtained, and is characterized in that a subtraction operation is performed
on effective picture element data obtained by electrically charging picture elements
2, and correction picture element data obtained in a state where gate lines
9 of picture elements 2 are not selected, and the quality of the
picture elements 2 is determined based on the subtraction output.
