APPARATUS AND METHOD FOR INSPECTION OF LIQUID CRYSTAL DRIVING BOARD

PROBLEM TO BE SOLVED: To obtain an apparatus and a method in which a liquid crystal driving board can be inspected with good accuracy, by a method wherein a low-frequency component is removed from an image signal obtained from reflected light from a dielectric reflecting film, and a binarization processing operation is performed. SOLUTION: Many pixel electrodes a2 are installed in a matrix shape on a liquid crystal driving board A. A modulator 1 is formed in such a way that a thin-film transparent electrode 1b is pasted on one face of a liquid crystal sheet 1a and that a semiconductor reflecting film 1c is vapor-deposited or pasted on the other face. The semiconductor reflecting film 1c is faced downward so as to be fixed to an inspection apparatus body. The liquid crystal driving board A is arranged so as to be faced by keeping a very small gap Δd in the lower part. A prescribed voltage is supplied to the pixel electrodes a2 and the transparent electrode 1b from a power-supply device 10. The modulator 1 is irradiated with light from a light source 4 via a beam splitter 3, a filter 5 and a lens 6. A reflected image from the semiconductor reflecting film 1c is photographed by a CCD camera 7. An image processor 8 removes a low-frequency component containing a DC component from its image signal so as to perform a binarization processing operation. A defective pixel electrode is detected, and its result is outputted to a monitor 9.